Maximum overcurrent protection on a plug circuit

[AndyD]

There's several separate issues though, whether like for like replacement requires a Coc and whether like for like replacement requires full testing and remedial work if it fails. TBH I'd expect even a DIY'er to plug a socket tester in after a like for like replacement.

I think there's a good arguement that regulation changes should apply retrospactively to older installations, especially with regard to the safety oriented regs. There could be a grace period of maybe five years but I'd at least like to see all domestic premises with RCD protection by now and also conforming to the later earthing and bonding regs.

[Slow Blow]

\ TBH I'd expect even a DIY'er to plug a socket tester in after a like for like replacement.

Most of the "electricians" who come to me for a job don't know what a socket tester is

[ians]

I would agree that replacing one socket outlet for another of an identical type, should not necessitate a certificate of compliance. However,
Imagine the circuit was old and had steel pipes.
The earth wire is Bonded onto the steel pipe and does not travel down the pipe to the socket outlet.
Now the circuit needs to be upgraded to accommodate the new 16 amp socket outlet.
Many times i've seen the situation where the steel socket outlet is removed and replaced with a plastic one without addition of a correct earth wire being installed.

If I recall a while back I started a thread with this issue. I was called out to look at something to find that the 4x2 sso had been replaced with DSO and a 4x4 extension box. The steel piping was used for earthing as was done back in the day. The electricians fitted new plastic DSO with no earth for the entire house.

[ians]

Most of the "electricians" who come to me for a job don't know what a socket tester is

You should try go on a certificate of compliance refresher course if you want to see how bad it really is

[ELECT 1]

Is a COC is necessary if replacing a plug .?? This assuming its done by an electrician. A pvc plug fitted to an old 30 amp system where the box is the earth, you will require an earth wire from the plug to the box. Now the dilemma, some school of thoughts say you must rewire and fit a separate earth wire, as you now cant use the conduit as the earth.
Some just screw an earth wire with a lug onto the plug box and earth the plug this way. So the plug is now earthed.
Now do you need a compliance, well if you rewire, i say yes, if you made the earth loop ( if allowed )to the box i say yes, as you have now altered the installation.
Otherwise just a normal replacement, i cant see why a COC would be necessary. Like if you need new brakes on your car, do you need a road worthy, need a service, do you need a roadworthy.

My 2c worth

[ians]

A trick question while on the subject of socket outlets.

What do you do if there is a 20 amp breaker and the customer complains it is tripping when he plugs in his old wire wound welder (for domestic sparkies) or you work in a franchise where some of the single phase heating/motor equipment (for the commercial sparkies) draws more than 20 amps never mind 16 amps on start up.

[Sparks]

Maitenance does not require certification. Earthing or providing an earth where there is one does not require certification. Where an earth is not available, you are obligated to provide one. If it means from the DB, so be it, the client must be made aware of the danger and legal requirement which will make him prepared to pay for it. This need not be certified. Should the client require a COC for your work he must be prepared to pay for it as it is your time compiling it. You are only obligated to certify your own work unless commissioned to certify the entire installation. Doing maintenance correctly is not changing/altering an installation. By putting an earth in from the DB you have not altered the amount of circuits nor the amount of points. These details are recorded on the COC. If you have the correct earth continuity reading for your circuit I find no fault in using the metal box for your earth. I would however inform the client that the 30A CB must be downgraded in order for the maintenance to be carried out legally and correctly.

[Sparks]

I would inform him that his welder draws too much power for the circuit and he needs to put in a new, stronger circuit or get a smaller welder if it is not justified by the amount of welding he does.

Unless of course he wants to do what we did as kids with the overhead wires which I will not explain here.

A trick question while on the subject of socket outlets.

What do you do if there is a 20 amp breaker and the customer complains it is tripping when he plugs in his old wire wound welder (for domestic sparkies) or you work in a franchise where some of the single phase heating/motor equipment (for the commercial sparkies) draws more than 20 amps never mind 16 amps on start up.

[gobbleteller]

Overload protection, like circuit breakers is primarily to protect the cable that it supplies and not the individual equipment attached to it.

In an industrial setting, provided the circuit conductors allow for it, I would up the rating of the circuit breaker: If the conductors of the circuit are 2.5mm2, I'd up it to a 25A CB, if 4mm2 the maximum you would be able to go is 43A.

For the domestic installation, there may be several circuits being fed from that CB. I'd determine the maximum current that would be drawn by the welder from the nameplate, and provided this doesn't exceed the socket outlet rating and assuming the circuit is wired with 2.5mm2 and more, I'd bump up the CB to a 25A

A trick question while on the subject of socket outlets.

What do you do if there is a 20 amp breaker and the customer complains it is tripping when he plugs in his old wire wound welder (for domestic sparkies) or you work in a franchise where some of the single phase heating/motor equipment (for the commercial sparkies) draws more than 20 amps never mind 16 amps on start up.

[ians]

The answers i expected, and the plug socket and plug top which os only rated at 16 amp?

[Sparks]

Which is why after my welder, which I installed a 4mm circuit with a welding plug for, was stolen, I replaced with an inverter. Nice and light to work on a ladder with too. No need for long heavy cables.

[Leecatt]

Maitenance does not require certification. Earthing or providing an earth where there is one does not require certification. Where an earth is not available, you are obligated to provide one. If it means from the DB, so be it, the client must be made aware of the danger and legal requirement which will make him prepared to pay for it. This need not be certified. Should the client require a COC for your work he must be prepared to pay for it as it is your time compiling it. You are only obligated to certify your own work unless commissioned to certify the entire installation. Doing maintenance correctly is not changing/altering an installation. By putting an earth in from the DB you have not altered the amount of circuits nor the amount of points. These details are recorded on the COC. If you have the correct earth continuity reading for your circuit I find no fault in using the metal box for your earth. I would however inform the client that the 30A CB must be downgraded in order for the maintenance to be carried out legally and correctly.

1./ "Earthing or providing an earth where there is one does not require certification. "
The earth wire is your most important part of your electrical circuit and installing one constitutes an alteration to that circuit and as such requires a COC issued.

2./ "You are only obligated to certify your own work unless commissioned to certify the entire installation"
I disagree here as well for the following highlighted reasons

OCCUPATIONAL HEALTH AND SAFETY ACT, 1993 ELECTRICAL INSTALLATION REGULATIONS
Issuing of certificate of compliance
9. (1) No person other than a registered person may issue a certificate of compliance.
(2) A registered person may issue a certificate of compliance accompanied by the required test report only after having satisfied himself or herself by means of an inspection and test that
(a)a new electrical installation complies with the provisions of regulation 5(1) and was carried out under his or her general control; or
(b)an electrical installation which existed prior to the publication of the current edition of the health and safety standard incorporated into these Regulations in terms of regulation 5(1), complies with the general safety principles of such standard; or
(c)an electrical installation referred to in paragraph (b), to which extensions or alterations have been effected, that
(i) the existing part of the electrical installation complies with the general safety principles of such standard and is reasonably safe, and
(ii) the extensions or alterations effected comply with the provisions of regulation 5(1) and were carried out under his or her general control.
(3)If at any time prior to the issuing of a certificate of compliance any fault or defect is detected in any part of the electrical installation, the registered person shall refuse to issue such certificate until that fault or defect has been rectified: Provided that if such fault or defect in the opinion of the registered person constitutes an immediate danger to persons in a case where electricity is already supplied, he or she shall forthwith take steps to disconnect the supply to the circuit in which the fault or defect was detected and notify the chief inspector thereof.
(4)Any person who undertakes to do electrical installation work shall ensure that a valid certificate of compliance is issued for that work.

[Dave A]

Well argued on the interpretation of this section of the regs, Leecatt.

It's something of a Catch 22 though when you can't issue the COC on the part of the installation you worked on, because some other part of the installation (which you didn't work on) isn't up to standard. And now you're responsible to ensure that magically this other part is brought up to standard?

What do you do? Hold a gun to the user/lessor's head?
Do the fix for free?
Not exactly what the contractor signed up for when they were contracted to add a plug point (or replace a faulty one for that matter)

I'm starting to think there's scope for a change in the regs here. Perhaps something that allows the registered person to report non-compliance to the supply authority?

Dunno for sure - just thinking out loud here.

[gobbleteller]

Ians, to tell you the honest truth, I have no domestic installation knowledge. I work on the mine and thus have no exposure to the domestic side of our industry. All I'm saying is that as long as amperage drawn by the welder isn't higher than the rating of the socket outlet supplying it, I would up the circuit overload protection. Being a domestic welding machine I'd assume it would be fitted with a 16A plug, in other words the welding machine must be rated at less than 16A. If you can't read the nameplate, test the current drawn by the welding machine. If the current drawn by the welding machine is higher than the 16A of the socket outlet and plug, then a separate circuit and male-and-female welding plug will be needed as Sparks mentioned.

The answers i expected, and the plug socket and plug top which is only rated at 16 amp?

[ians]

" then a separate circuit and male-and-female welding plug will be need"

That was the answer I was looking for, plug and socket rated correctly.