Frequently Asked Questions
FAQs on:
Electrical
Contractors.
Routine safety checks.
Airing Cupboards
Attics.
Bathrooms.
Cables.
Distribution Boards.
Sockets, Light Switches, Lights.
Periodic Inspection and Testing
Industrial/Commercial Installations.
Overhead lines and Electricity Pylons
Effects of Electricity on the Human Body
Residual Current Devices (RCDs)
Modular
Residual Current Devices (MRCDs)
Training Requirements - Electrical Contractors and
Electricians
Competent Person (Definition: Safety, Health &
Welfare at Work Act 2005)
Q:
Where can I get a reliable Electrical Contractor?
A: There are two Registers of Approved Electrical Contractors in
Ireland whose members claim that their work complies with the National
Rules for Electrical Installations - "The Wiring Rules". These
are:
Q:
Are there any simple checks which a non-technical person can make to monitor
an electrical installation?
A: Yes, any change in the behaviour of an electrical installation
should be checked e.g. fuses blowing more than once, lights flickering.
Installations should be tested by a competent electrician about every
5 years.
On a regular routine, sockets, switches and appliances should be inspected
by the householder or equivalent for signs of overheating, wear on flexes,
plugtops are properly connected - the colour of the wires in a flex entering
a plug-top should not be visible from outside the plugtop. A cord grip
should hold the outer sheath of the flex, not the coloured cores. Other
faults include:
- Damage to plug tops such as cracking, heat discoloration, missing screws
etc.
- Damage to flexible cables
- Unearthed equipment. If the flex has 3 cores it normally requires earthing.
- Dangerous joints in flexible cables including taped joints. Proper extension
units should be used.
- Appliances should not be used in unsuitable locations, or if damaged.
- In replacing fuses the correct fuse should be used.
Since 1980 socket circuits should be protected by a trip-switch (RCD)
to prevent electric shock. There should be tested every 3/6 months by
pressing the test button.
Q:
Are there special requirements relating to electrical equipment in airing
cupboards?
A: Yes, because of the temperatures and low humidity in an airing
cupboard timbers tend to dry out and become more flammable. The electrics
in an airing cupboard should be limited to those items mentioned in the
Wiring Rules such as the wiring to the immersion group. Preferably, switches
should be mounted outside the airing cupboard but where this is not possible
or desirable they can be installed within the cupboard provided certain
precautions are taken as outlined in the Wiring Rules. Because of the
daily use and frequent and rough usage in an airing cupboard the electrical
installation tends to deteriorate quickly and it should be examined regularly
to ensure that there is no damage to the cabling and switches etc. which
might cause a fire.
Q:
Is there some change in requirements for wiring in attics?
A: Not really, wiring anywhere requires the use of common sense
and the protection of cables and equipment. However, in recent years the
conversion of attics into habitable rooms by laying floors, etc by unqualified
and incompetent people has introduced a new hazard. In the past contactors
frequently just laid cables over joists in attics without the expectation
that these rooms might be floored. Laying flooring panels over joists
and sandwiching or trapping cables between the panels and the joints can
cause damage to the cables resulting in a breakdown in insulation and
possible fires etc. This danger in now being highlighted.
Q:
Why are Wiring Rules so strict for bathrooms?
A: Because in the normal house the bathroom is the most dangerous
room in the house. An electric shock in a bathroom is often fatal. Nearly
every year someone is electrocuted in a bathroom because of breaches in
the wiring. Remember with electricity, because it works does not mean
that it is safe.
Q:
Is it safe to install an instant shower in an existing installation?
A: Showers nowadays are amongst the most demanding of all domestic
appliances. It is not unusual to find showers of 9 or 10 kW and obviously
their installation could impose unacceptable demands on the system, particularly
if it is an old installation.
Any installation to which it is proposed to add an instant shower should
always be checked by a competent person to see that the supply and existing
installation is capable of handling the additional load without reinforcement.
Where two showers are proposed to run concurrently, reinforcement or controls
will almost certainly be necessary and two separate circuits should be
used. Where the two showers do not have to be on simultaneously this can
be arranged by electrical interlocking.
Q:
Are phones allowed in bathrooms?
A: Mains phones are not allowed in bathrooms. If you require a phone
in a bathroom you should either use a mobile phone or bring in a cordless
phone.
Q:
Why was it necessary to change the colour cores of fixed cables after
so many years?
A: With
the establishment of the EU, or as it was known in earlier days the EEC,
it was decided to rationalise the electrical installations rules for member
countries so that the same Rules applied throughout Europe.
It was accepted that this would be a slow process as the Rules in each
country had been set up many years before. Hence negotiating changes would
be an extremely difficult process. This would be particularly difficult
in what might be called the non-technical areas such as the colours of
various cable cores and other traditional practices.
Of immediate concern was adopting a common colour code for flexible cables
on appliances and this was driven hard by appliance manufacturers so that
they could export their appliances throughout Europe and world-wide. This
was achieved in the early 1970s and was indeed a major achievement when
one remembers that while we regarded red as a phase colour, in Germany
red was the earthing conductor. Similarly various conductor colours were
used by different countries.
Agreement was not as quickly reached with regard to fixed or permanent
wiring, although Europe did agree to a common colour for the neutral during
the 1970s.
It was only recently that agreement was reached on phase colours and henceforth
these will be:
Neutral - Blue
Phases - Brown, Black, Grey.
Q:
Why do the Wiring Rules place so much importance on the location of the
Distribution Board?
A: The
Distribution Board is an extremely important part of an electrical installation.
It is the safety control of the electrical installation. It provides two
essential functions:
(1) - The overload, short circuit and earth fault protection.
(2) - the isolating function of the installation.
Obviously to provide these functions it must be protected against abuse
either mechanical or environmental. It must be readily accessible at all
times and it must properly ventilated. Distribution Boards, dissipate
heat and have been known to overheat and this must be considered in their
installation and location.
Q:
We have heard of holiday cottages that do not appear to have an adequate
supply for the installed load. The problem seems to occur particularly
at night when new tenants arrive after the cottage has been unoccupied
for a while.
A: Problems
such as this probably occur where people switch on an abnormal load in
the cottage perhaps to heat up the rooms. No domestic installation is
designed to have every appliance switched on at the same time.
The designer normally assumes that only a certain percentage of the total
load will be on at any one time and designs accordingly. If he were to
assume that every electrical appliance and light in a domestic house was
switched on at the same time the electricity supply from the Supply Authority
would seldom be used to its capacity and would be much more expensive
to provide than the normal supply which is based on an average maximum
usage.
Users should remember this and, particularly in cold weather, when arriving
at a holiday home they should not switch on everything together. This
of course applies to any normal installation but holiday homes seem to
suffer more.
Q:
Do brass wall light switches and metal luminaires (light fittings) have
to be earthed?
A:
Yes, since January 1998 all wall light switches and
lighting points must be earthed.
Q:
Must sockets be mounted away from sinks?
A:
There is
no specified distance given in the Wiring Rules. Common sense would require
that they are not mounted where the sockets or connected appliances can
be splashed from the sink or taps.
Q:
Why do the Wiring Rules not specify the numbers of socket outlets that
should be provided in the kitchen?
A:
The
National Wiring Rules do recommend a minimum of 10 socket outlets in a
kitchen. This however is not a question of electrical installation practice
but rather a matter of house design for the Department of Environment
or the Building Regulations. The fact that the recommendation of 10 socket
outlets is made in the Rules could be regarded as a considered view, not
alone of the ETCI. The installation of less of 10 socket outlets in the
kitchen might be regarded as inadequate for a normal kitchen in this day
and age.
Q:
How many points should a final circuit in a domestic premises supply?
A: This
depends whether the circuits are radial or ring final circuits.
For a radial circuit the maximum number of points recommended is 10 per
circuit. This applies to either lighting circuits or socket outlets etc.
In the case of socket outlets a twin socket outlet would count as one
point. For final socket circuits it is recommended that a radial circuit
should not serve more than two rooms.
For ring final circuits the number of points is unlimited within a floor
area of 100 sq. meters.
Q:
Why are the heights of wall switches for lights, lower than before. Is
this not more dangerous as children can now operate them?
A: The Department of Environment has directed that lighting wall switches
should not be higher than 1200mm or lower than 900mm. This is to allow
easier access for people with special needs or disabilities.
It
will of course be easier for children to operate them but if properly
installed there should be no great danger. After all sockets and table
lamps are frequently below this height.
Q:
Some lampholders seems to become brittle after a relatively short time
in use. Why is this?
A: This is usually due to overheating either
because of inadequate ventilation of the bulb or lampholder or by installing
a bulb rated above the thermal capability of the lampholder.
Lampholders marked T1 for example are not designed for incandescent lamps
rated above 60W.
Q:
Are there special plugs and sockets for outdoor installations and if so
why?
A: Yes. We like most mainland Europe countries do not consider indoor
plugs to be suitable for outdoor installations subject to weather and
rough handling and so ordinary 13A sockets to I.S. 401 are not suitable
for outdoor use. Like all socket outlets up to 32A, they should be protected
by an RCD. The Rules require that outdoor sockets and industrial sockets
comply with IS/EN60309 standard. In this system both the plug and socket
are hard wearing and are deemed to be suitable for outdoor use. The single
phase plug is coloured blue and the socket is inclined towards the ground
to prevent the ingress of moisture. They may be more cumbersome than the
flat pin plug system but they are safer.
Q:
As a letting and property management agency, we would like to enquire
how often the ETCI periodic testing is required in rented accommodation.
Do you have any literature on this?
A: Regulation 89(b) of SI 299 of 2007, as amended by SI 732 of
2007 applies to the workplace and requires that an employer shall ensure
that existing electrical installations be tested by a competent person
from time to time (periodically), that a report be completed and that
all defects found during the testing and inspection be rectified promptly
so as to prevent danger.
HSA
guidance in this area indicates that correctly functioning RCDs are key
to minimising risk and preventing shock or electrocution. An RCD must
be tested by regular operation of the test trip button, as stipulated
by the device manufacturer This would ensure that the RCD would be less
likely to fail to operate when needed as any stiction difficulties
(electro-mechanical protective devices that are exposed to any moisture
and dust are likely to stick if not operated periodically) would be overcome.
While
the push to test should ensure that the RCD will operate when
required, it should also be functionally tested by a competent person
periodically to ensure that it operates for the rated leakage current
(e.g. at 30mA) and within the time permitted (e.g. < 0.3 seconds).
Such testing should form part of the periodic installation tests as outlined
in Regulation 89 (b).
ETCI
fully supports the HSA guidance in this area. ETCI also recommends that
the 'push to test' button be operated at least twice per year and suggest
that this be undertaken in March and October when the clocks are put forward
or back.
There is also other legislation in place, e.g. 'The Housing (Standards
for Rented Houses) Regulations 2008'. Its Regulation 13 states: Electricity
and Gas - Installations in the house for the supply of electricity and
gas shall be maintained in good repair and safe working order with provision,
where necessary, for the safe and effective removal of fumes to the external
air.
The Technical Guidance Document for the regulations states: The following
will prove compliance with the Regulations: A current ETCI Periodic Inspection
Report by a registered electrical contractor for the electrical installation
in the house. The result of the tenancy inspection shall show a standard
which requires that "no remedial work is required".
Dublin
City Council Environmntal Health Department have put a policy in place
that fully complies with this legislation and ETCI recommends that such
a policy would be appropriate to others in the Letting and Property Management
business. Contact Dublin City Council for details.
As
for places of employment, be it your own home or be it rented accomodation,
ETCI also recommends that the 'push to test' button be operated at least
twice per year and suggest that this be undertaken in March and October
when the clocks are put forward or back. In addition ETCI recommends that
SMOKE DETECTORS be checked be tested at least every March and October..
Q:
When working on 20kv switchgear e.g. resetting tripped breakers etc.,
should there be a second electrician present who is trained in high tension
practices?
A: This query is not covered by anything
in ETCI's Wiring Rules as these rules relate to LV only. However this
question does have an answer when considered under statutory requirements
(refer to the Safety, Health and Welfare at Work (General Application
Regulations) 2007 (S.I. 299 of 2007 and its amendmend S.I. 732 of 2007,
Part 3 - Electricity)) under two headings as follows:
Is the work classified as 'live work' or 'work on or near any exposed
live parts'? (see regulations 86 and 88 of S.I. 299 of 2007 and see also
ETCI's publication 'The Management of Electrical Safety at Work ET206:2009').
The HSA guide to the regulations recommends that:
- 'where
high voltage live working is being carried out another person should
be present at all times' and
- where
work on or near a live part is unavoidable, the system of work used
should:
- allow only a person who is competent (see regulation 48) to work on
or near exposed, live conductors. Such a person should be accompanied
by a second person who is trained and able to act in an emergency, e.g.
switch off power and give first aid treatment for electric shock'
- 'indicate the extent of the live work'
- 'indicate what levels of competence apply to each category of work'
and
- 'incorporate procedures under which the person carrying out the work
will report back if the limits specified in the system are likely to
be exceeded. This usually requires detailed planning before the work
is started'
- Where
the work is not 'live work' or 'work on or near any exposed live parts',
then it's your 'risk assessment' that should guide you towards having
the necessary controls in place to ensure that the work can be carried
out safely.
In
general:
- 'With
properly installed and maintained equipment that is rated for the intended
operating conditions (i.e. is suitably covered/insulated/screened, is
rated to make or break fault currents and has properly designed control
and protection systems), there is minimum risk to the person operating
this equipment and therefore such an person could safely undertake this
work while alone.
- If
your risk assessment showed that it was unsafe for a person to work
alone, would two or more persons not also be in danger in such circumstances.
- Whenever
and wherever possible it is best to operate switchgear remotely. Local
operation should only be a last resort. That said, quite an amount of
switchgear is manually operated and is so designed to be safely operated
in this way.
Note:
All references to regulations in the above question are to the Safety,
Health and Welfare at Work (General Application Regulations) 2007 (S.I.
299 of 2007 and its amendment S.I. 732 of 2007, Part 3 - Electricity).
Q
Where would I get information on Overhead Lines and Electricity Pylons
A
ETCI's publication ''Guide to the Basic Principles of Electrical Safety'
has a small section dealing
with Electric and Magnetic Fields (EMF). You may however find much more
information on EMF and pylons either on the ESB website (www.esb.ie)
or on the Eir Grid website (www.eirgrid.com)
or on 'The International Commission on Non-Ionizing Radiation Protection
(ICNIRP)' website (www.icnirp.de).
The
Health and Safety Authority (www.hsa.ie)
may also have some safety information with regard to work near overhead
lines and underground cables (as there are statutory requirements in this
area under Regulation 93 of the Safety, Health and Welfare at Work (General
Application) Regulations of 2007 (S.I. No 299 of 2007). ESB Networks also
has a guidance booklet on 'The Avoidance of Electrical Hazards when Working
near Overhead Lines' (available free from ESB).
Note
that there are no statutory limits set down for the height of electricity
wires that are supported by pylons. However regulation 93 (1) in S.I.
No 299 of 2007 states that:
An
employer shall ensure that-
(a)all
overhead lines and their supporting structures and underground cables
are constructed, installed, connected and maintained in a manner suitable
for the work and conditions under which they are to be operated to prevent
danger,
and
(c) all overhead lines and other current-carrying parts connected to
or containing part of overhead lines are arranged so that adequate clearance
is provided from the ground or other accessible place to prevent dangerous
contact with a person, article, substance or any conducting material,
If you need details of the actual clearance (height above ground) for
ESB overhead lines (different clearances are laid down by ESB for a variety
of situations and for the different voltage levels that exist on these
lines), you should contact ESB Networks. In general the clearances used
by ESB are
very similar to those that apply in other Utilities throughout the worls,
as are the protective measures that are put in place to minimise the risks
to both workers and the general public.
Dangers
of Electricity
Q:
Why is Electricity Dangerous?
A: Electricity
can and does KILL people.
Electricity
for domestic use is normally supplied at 230V. For industrial use it can
be supplied at 230V or 400V. On building sites it is common practice to
find isolation transformers with a secondary voltage of 110V which has
the centre point connected to earth. This ensures that if the user touches
a live wire the maximum voltage on the body will be 55V, which is considered
to be safe. IEC (the International Electrotechnical Commission) actually
specifies 50V as the maximum safe touch voltage. However, most people
have to use electricity at 230V and this is clearly well above the recognised
safe levels.
Q:
What are the Effects of Current Flow Through the Human Body?
A: The
following information is based on studies carried out by Professor Biegelmeier,
Dr. Osypka, and the IEC.
The
behaviour of the human body when exposed to an AC voltage is interesting
in that the resistance of the body falls as the voltage increases. According
to IEC data, 95% of people could be considered to have a body resistance
of less than 4,375 ohms at 50V, but at 220V the body resistance falls
to about 2,125 ohms for the same grouping. The reason for the fall in
body resistance is mainly due to breakdown of skin resistance with rising
voltage, the internal body resistance remaining relatively constant for
voltages up to about 500V. It is also important to note that the value
of 2,125 ohms is an average for the 5% group and that lower body resistances
may apply depending on age, gender, climatic conditions, etc. For guidance
we can assume that the body resistance will rarely exceed 2000 ohms at
230V. This would result in a current of at least 115mA flowing through
the body at that voltage.
When
a person touches a live part the current flow through the body will usually
be through hand and feet, or hand and feet and other hand if the other
hand is touching an earthed part. The body resistance falls as the touch
voltage increases, and in the case of touch voltages >1000V the body
resistance can fall to such an extent that currents of ampere levels can
flow through the body. However, for RCD protection we are generally dealing
with touch voltages of around 230V, although touch voltages of up to 400V
can apply in industrial situations. The current that will flow through
the body from hand to feet will depend on the body resistance. However,
this current will also depend on the resistance at the contact point,
e.g. touching or holding a live wire, and the resistance at the earthing
point, e.g. rubber or leather shoes, etc. Due to this combination of resistances,
the actual current flow through the body at 230V can vary from virtually
zero upwards.
The usual reaction to an electric shock is to instinctively pull away
from the live part. However, a person holding rather than touching a live
wire may not have the ability to let go because when the AC current through
the body exceeds a certain level (the release level) the muscles can freeze
and prevent normal muscular action.
According to IEC60479, two key levels of electric current need to be considered
with regard to shock protection.
The first is the "let-go" level, which is generally accepted
to be around 7mA. At or above this level, muscles may seize, and a person
touching or holding a live part may not be able to let go of the live
part. RCDs rated up to 10mA are intended for protection against "let-go"
currents, and are recommended for use in hospitals and old people's homes
or similar locations.
The second is the "fibrillation" level, which is generally accepted
to be around 50mA. At or above this level, heart fibrillation is likely
to occur. RCDs rated up to 30mA are the upper limit for RCDs intended
to provide shock protection.
The following provides an indication as to likely effects on the body
for currents at different levels.
- For
currents up to about 1mA, there will be little or no sensation of a
shock.
- For
currents of 1 - 10mA there may be a moderate to strong sense of pain
in the joints and muscles of hands, arms and feet. Let go may be difficult.
- For
currents of 10 - 200mA, muscular freezing is likely to prevent let-go.
There may be severe pain in muscles and joints, increased blood pressure
and difficulty in breathing. There is a risk of heart fibrillation.
- For
currents >200mA there will be an increasing risk of heart fibrillation
and irreversible heart damage.
Q:
How is the use of electricity made safe?
A: There
are three basic measures used to provide protection against electric shock.
These are;
- Isolation
of live parts: Consider the basic socket outlet where live parts are
concealed within the socket. Modern socket outlets are fitted with shutters
to further improve isolation.
- Insulation
of live parts: Electric wires and cables are usually covered with plastic
insulation to prevent people touching live wires.
- Earthing:
Metalwork such as cooker bodies, etc. are connected to earth to prevent
them from becoming live and dangerous to touch.
Residual
Current Devices (RCDs)
Q:
What are RCDs?
A:
RCDs are devices that provide protection against electrical currents
flowing to earth. Such current could flow to earth through a person's
body and present a shock risk, or flow through wiring or electrical appliances
and present a fire risk
Q:
Why use RCDs?
A: The
three basic measures do provide a very high degree of protection against
electric shock. Just imagine how dangerous your home or workplace would
be if
any one of the above protective measures was not provided. However,
circumstances do arise where one or more of the three basic protective
measures fails, for example a breakdown in insulation between a live part
and metalwork, exposure to live parts when changing fairy lights in a
Christmas tree, cutting of a cable with an electric lawn mower, etc. Under
such conditions, an RCD can provide an additional level of protection
against electric shock.
Q:
How do RCDs work?
A:
Under
normal conditions the current flowing in the live conductor (I L) will
be the same magnitude as the current flowing in the neutral conductor
(I N). The two conductors are passed through a current transformer (CT)
in the RCD, and the CT will produce an output when it sees a difference
in these two current magnitudes. Under a fault condition, for example
a person touching a live part, an additional current (I F) will flow to
earth back to the supply. Current I L will now be greater than current
I N and the CT will produce an output in proportion to this differential
current. If the differential current is above the predetermined trip level
of the RCD, the contacts will automatically be opened thereby providing
protection against electric shock.
The
term "Residual" in Residual Current Device implies that there
is a residual current flowing in the circuit over and above that required
to provide power to a load.
Q:
At What Current Level Do RCDs Operate?
A: The operating current level of RCDs depends on the application
of the RCD. If the RCD is intended primarily for electric shock protection,
the operating level will typically be 10mA or 30mA. RCDs can also provide
some protection against electric fires caused by larger current flows
to earth. These RCDs typically have an operating current of 100mA or 300mA.
It is important to note that 100mA and 300mA RCDs are not suitable for
personal protection against electric shock because the operating current
would exceed the let-go and heart fibrillation current levels.
Q:
How Fast do RCDs Operate?
A: In general, RCDs respond faster to higher fault currents and
slower to lower fault currents. There are two reasons for this.
- The
studies into the effect of current flow through the human body indicate
that the body can withstand relatively low current levels for longer
periods than higher currents. If this characteristic was plotted on
a graph it would reveal a body withstand duration which was roughly
inversely proportional to the current levels. The RCD can be designed
to mimic this characteristic by making it respond faster to higher fault
currents and slower for lower fault current levels.
- If
RCDs were made to respond equally fast for high and low fault current
levels, there would be a high risk of nuisance tripping of the RCD in
response to momentary earth currents, such as those arising from voltage
spikes, surges, starter motor inrush currents, etc. Bear in mind that
the RCD is intended to provide additional protection only in the event
of failure of one of the three basic forms of protection, and as long
as these are intact the RCD does not need to operate.
Q:
In What Form Are RCDs Available?
A:The term RCD is a generic term which is applied to the whole
family of RCD products. RCDs are generally available in four forms as
follows:
- RCCB,
which is a Residual Current Circuit Breaker.
This is basically a mechanical switch which can be manually opened and
closed, and which is fitted with an RCD function to enable it to automatically
disconnect power in the event of an earth fault. These are available
with trip current ratings of 10 - 500mA.
- RCBO,
which is a Residual Current Breaker with Overcurrent protection.
This is basically a circuit breaker which can be manually opened and
closed, which can automatically open in the event of an overload current
condition, and which is fitted with an RCD function to enable it to
automatically disconnect power in the event of an earth fault. These
are available with trip current ratings of 10 - 500mA.
- SRCD,
which is a Socket outlet which is fitted with an RCD function to enable
it to automatically disconnect power in the event of an earth fault.
These are available with trip current ratings of 10 or 30mA.
- PRCD,
which is a Portable plug or adaptor which is fitted with an RCD function
to enable it to automatically disconnect power in the event of an earth
fault. These are available with trip current ratings of 10 or 30mA.
Q:
What Standards Cover RCDs?
A: RCDs are generally covered by international or national standards.
IEC, which is the world body responsible for standardisation in the electrical
industry, publishes product standards for countries world-wide. These
standards usually have the prefix IEC, e.g. IEC61008. Adoption of these
standards is not mandatory but many countries adopt IEC standards as national
standards, sometimes with modifications.
CENELEC is the European body responsible for standardisation in the electrical
industry and seeks to maximise standards harmonisation within Europe.
International standards published by IEC are usually adopted by CENELEC
(possibly with modifications). CENELEC usually replaces the IEC prefix
with one of two prefixes as follows:
- EN,
a European Norm, e.g. EN61008. When an EN is published, CENELEC member
countries must replace any conflicting national or IEC standard with
the EN version.
- HD,
Harmonisation Document, e.g. HD60384. When an HD is published, member
countries are required to adopt the HD but may modify it to suit national
conditions or practice.
- When
a CENELEC member country adopts a CENELEC standard, it usually adds
a prefix to indicate that country's identity. In Ireland's case the
identity is IS, e.g. ISEN61008.
RCDs
are covered by the following standards. In some cases the IEC standard
is still under review in IEC or CENELEC and awaiting formal adoption by
member countries.
RCCBs
IEC61008, EN61008, ISEN61008
RCBOs IEC61009, EN61009, ISEN61009
SRCDs IEC61541 (presently being prepared)
PRCDs IEC61540 HD61540
IEC,
CENELEC and National Standards can also have subsections to cover different
types of RCDs within the main standard, as follows.
RCCBs
ISEN61008-1 = Main body
ISEN61008-2-1 = Section applicable to voltage independent RCCBs
ISIEC61008-2-1 = Section applicable to voltage dependent RCCBs
RCBOs
ISEN61009-1 = Main body
ISEN61009-2-1 = Section applicable to voltage independent RCBOs
ISIEC61009-2-1 = Section applicable to voltage dependent RCBOs
Q:
Where Should RCDs be Fitted?
A: The Irish Wiring Rules, (the Rules), more correctly known as
the National Rules for Electrical Installations, Third Edition, ET 101,
current edition, as published by the Electro-Technical Council of Ireland
sets out the requirements with regard to the use of RCDs in Ireland.
Q:
Where can I get more information about the use of RCDs?
A: ETCI has published a Guide to the Use of Residual Current Deices,
ET214, which is freely available from ETCI and may be downloaded
here (pdf
document, 90kB).
Q:
I have a 30mA RCD fitted in my house and it keeps tripping for no apparent
reason. What can I do?
A: Get an electrician to check the installation. The RCD tripping
could be an indication of a deterioration in the electrical insulation
of wiring or appliances.
Q:
I have a 30mA RCD which occasionally trips for no apparent reason. Can
I simply change it for a 100mA unit?
A: No. The 30mA RCD was installed to provide shock protection.
This cannot be assured by a 100mA RCD because it may prevent let-go and
heart fibrillation. The RCD may be of an older design which is prone to
nuisance tripping. Try having it changed for a new one.
Q:
How often should I test the RCD?
A: Manufacturers tend to advise users to "test often"
or "test frequently", but these terms are not defined. Testing
every 3 - 6 months would be considered acceptable where the RCD is fitted
in a consumer unit and may be slightly inaccessible. However, SRCDs and
PRCDs could certainly be tested more frequently because of their ready
accessibility.
Use the changeover from Winter Time to Summer Time or vice versa as an
opportunity to test the RCD. You have to reset clocks anyway, so why not
test the RCD also.
Q:
What is a Modular Residual Current Device (MRCD) and where would it be
used?
A: A Modular Residual Current Device (MRCD) is a device or an association
of devices comprising a current sensing means and a processing device
designed to detect and to evaluate the residual current and to control
the opening of the contacts of a current breaking device. They are primarily
intended to be used in conjunction with circuit breakers in accordance
with IEC 60947-2. Normative requirements for MRCD's are described in Annex
M of IEC 60947-2. Copies of the Irish Standard implementation of the standard
(I.S. EN 60947-2) are available for sale at www.standards.ie.
Q:
Does an electrical contractor require a formal training to provide certification
as per ET215:2008.
In this document it makes reference to a competent person. Can you confirm
that a qualified electrician is covered to certify as a competent person?
A:
Competent Person:For the purposes of the relevant statutory provisions,
a person is deemed to be a competent person where, having regard to the
task he or she is required to perform and taking account of the size or
hazards (or both of them) of the undertaking or establishment in which
he or she undertakes work, the person possesses sufficient training, experience
and knowledge appropriate to the nature of the work to be undertaken.
In
order to carry out the certification for the maintenance and inspection
of Portable equipment, a competent person must possess the following:
(a)
Sufficient training
(b) Experience
(c) Knowledge appropriate to the nature of the work.
This
means that the three elements must be satisfied by the following:
(a)
Sufficient appropriate training is of a standard demonstrated by being
qualified to the National Craft Certificate (electrical) level or equivalent;
(b) Have sufficient experience (a newly qualified electrician may not
have sufficient experience, may require additional training and supervision);
(c) Must possess knowledge appropriate to the nature of the work; must
be in a position to carry out knowledgeable testing with appropriate test
instruments and be in a position to analyse the results and complete appropriate
test record sheets.
At
present a qualified experienced electrician is competent to carry out
testing and verification.
A
qualified electrician who has fulfilled (a) (b) and (c) above is competent
to carry out testing and verification.
Q:
As a manufacturing company we employ a maintenance electrician. The company
also regularly uses outside electrical contractors for both installation
and maintenance work. Please advise on the following:
(1)
What regulations are at present in force?
(2) What training with regard to the regulations should maintenance electricians
have (and is any mandatory)?
(3) What training with regard to the regulations should electrical contractors
have?
A: (1) What regulations are at present in force?
- The
Safety, Health and Welfare at Work Act 2005, from which most of the
present health and safety regulations emanate (see the 2 main sets
of regulations hereafter). It is here in this Act that you will find
a definition of a 'competent person' (has appropriate knowledge, training
and experience) and 'reasonably practicable' (many employer duties
apply 'so far as is reasonably practicable'
- The
Safety, Health and Welfare at Work (Construction) Regulations of 2006
(S.I. No. 504 of 2006). Note that the maintenance of electrical installations
comes within the definition of 'construction work'.
- The
Safety, Health and Welfare at Work (General Application) Regulations
of 2007 (S.I. No 299 of 2007 and its amendment S.I. No 732 of 2007).
These General Application Regulations are applicable to almost all
places of work, (as is the 2005 Act) and are made up of 8 parts that
contain many regulations (e.g. re the Workplace, Use of Work Equipment,
Manual Handling of Loads, Work at Height, etc.). Part 3 are the 'Electricity'
regulations (regulations 74 to 93) that set down the employer's duties
with regard to electricity (e.g. suitability of electrical equipment
and installations, portable equipment, switching and isolation for
work, competent persons, testing and inspection of new and existing
installations, etc.).
- The
Commission for Energy Regulation (CER) is at present finalising the
Criteria for the Regulation of Electrical Contractors and the selection
of Designated Bodies (which will have their own register of electrical
contractors). The training and competency requirements for contractors
undertaking a variety of electrical work activities may well be laid
down by the CER in consultation with the Designated Bodies and other
A:
(2) What training with regard to the regulations should our maintenance
electrician have? (and is any mandatory?)
- As
an employer you have a duty (under section 10 of the 2005 Act) when
providing instruction, training and supervision of your employees
in relation to their safety, health and welfare to ensure that it
is provided in a form, manner and language that is reasonably likely
to be understood. Training is therefore mandatory.
- Regulation
88 of the General Application Regulations of 2007 requires that an
employer shall ensure that no person is engaged in any work activity
to which Part 3 of the regulations relates, where technical knowledge
and experience is necessary to prevent danger, unless that person
is competent or is under such degree of supervision as is appropriate,
having regard to the nature of the work. You need to be satisfied
that your 'maintenance electrician' is competent.
-
A qualified electrician (through FAS/FETAC qualification), who fully
understands the requirements of the National Rules for Electrical
Installations (ETCI ET101) and who has the necessary competencies
with regard to the maintenance of your particular electrical installation
and equipment, including knowledge of new equipment now in use, should
be OK. But you, in particular, and he/she would need to be aware of
all that is required to fulfill your statutory duties under the Act
and its regulations.
A:
(3) What training with regard to the regulations should our contractor
have?
- The
same 'competency' requirements apply to a contractor as would apply
to any person undertaking any particular work activities. They should,
as an employer (even if self employed) fulfill their statutory duties
both for themselves and their own employees. They need to know and
understand these duties. In particular, under the Construction Regulations,
when it comes to construction type activities, contractors must comply
with Parts 3 to 14 (regulations 24 to 105) and co-operate with the
Project Supervisor for the Construction Stage of the project (whatever
that project may be). It would be your duty as the 'Client' (the person
for whom the work is being carried out) to appoint competent Project
Supervisors. See also Section 17 of the 2005 Act for more details
of a Client's duties and regulations 6 to 10 of the Construction Regulations.
- As
regards specific training courses that may be appropriate, ETCI offers
its 'Management of Electrical Safety at Work' course that is appropriate
to both you and your maintenance electrician. This course and its
associated publication ETCI ET206:2009 has been updated to take account
of recent legislation updates (electrical and construction) and also
the requirements coming through under the Commission for Energy Regulation.
-
ETCI also offers courses on the 'Verification and Certification of
electrical installations', on the 'Periodic Inspection and Testing
of Existing Installations', on the 'Maintenance, Inspection and Testing
of Portable Equipment'', on 'Electrical Installations in Explosive
Atmospheres' and finally on 'Basic Electrical Safety Guidelines'.
-
The Health and Safety Authority (HSA) or the National Irish Safety
Organisation (NISO) may well offer special courses with regard to
Health and Safety Legislation.
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