Consumer unit fitted, having problems

[NT]

In fairness the landlord doesnt know if the sparky is a k*****ad or not, though its a bit naive to just trust the first opinion that comes along, especially when it leads to the conclusion that a bunch of work is needed.

rather unprofessional

Sounds like he's been foolish. People are.

You might be able to resolve it by something like...

I'm offended by the way you've chosen to deal with this issue.

I've consulted ------- who confirmed that the type B overcurrent protection device your contractor fitted has a trip curve that is unsuitable for the load in use, and that it requires replacing with an HRC fuse & carrier for the circuit to function corrrectly. This will cost =A3quote to do, and since the problem has been introduced entirely by your own contractors I request that you resolve this at your expense within --- days. If this is not done I'll have the system put right and recover the cost of doing so plus the various costs of lost production time.

NT

[Mike Tomlinson]

In article , Dave Liquorice writes

A radial, not a spur. And if it's wired in 2.5mm T&E I believe a 20A breaker could be used.

[Jules Richardson]

Is there any possibility of changing the motor (and compensating for the speed change if needed)?

[jgharston]

Being non-domestic premises, it's not required to be MCB/RCD protected, insist on going back to a rewirable fuse consumer unit, though a quick skim of the faq and wiki don't give me an appropriate reference.

JGH

[RobertL]

On Nov 18, 9:41=A0am, Martin Brown wrote: >

Presumably it's not designed for 110 Volt like US equipment usually is.

Robert

[Martin Brown]

I think it would have expired with a blue flash and a shower of sparks long since if it was. Heavy industrial kit like larger power tools and some domestic aircon tend to be on 220v even in 110 mains countries.

[John Williamson]

Until the full info was posted, I saw no indication that this wasn't a new installation for the machine concerned. It also wouldn't be the first time someone stuck the wrong voltage label onto a machine.

14A draw as mentioned is within the norm for a 110V machine, is it not? Say a vacuum cleaner, which I know this isn't.

[John Rumm]

It could, but that might not fix the problem - the inrush could be over

100A and that will trip a B20.

(A C16 breaker has the same magnetic trip response as a B32)

[robgraham]

Interesting Adam - why can one just not swap to a C type. My previous circular saw motor tripped the MCB - it was hard wired onto a 20A trip

- so I just changed it for a C type and have had no more problems.

I assume that the measurements you are talking about is some sort of current/time profile and with all due respect to most sparkies I'm not sure that they wouldn't know what that even meant.

Rob

[John Rumm]

You need to ensure that fault protection is maintained. That means (in the case of a non RCD circuit) that the earth loop impedance at the furthest reach of the circuit is low enough to give adequate fault current to trip the higher threshold breaker on the magnetic part of its response.

With a RCD protected circuit, then you can ignore the ELI, but still need to check the similar circumstance with regards to the prospective short circuit current.

Basically what to make sure that swapping the breaker wont leave you finding that it now can't clear a line to neutral or line to earth fault quickly enough to minimise shock risk, and/or to prevent cable damage.

Most ought to be familiar with ELI and PSCC - even if all they know is that they are numbers their multifunction tester can give them!

[ARWadsworth]

As John said. It really is nothing more than a resistance reading at the end of the circuit.

The resistance needs to be low enough to trip the MCB in the correct time to prevent shock and cable damage. A C type MCB needs twice the current to pass than a B type if there is a short circuit so the maximum resistance allowed at the end of the circuit is half of that allowed for a B type MCB.

really would be nothing more difficult that plugging a proper tester into the end of the circuit and pressing the test button to check this resistance and you then just compare the results with the table on page 103 of the OSG.

John and I (plus quite a few other posters) could do the calculations with a tape measure and calculator if we knew what sort of a supply it was and where the cable ran. But I know that we are both far too lazy to do it that way:-)

[ARWadsworth]

The guy could be a part P electrician. That could mean that he got his certificate out of a cornflakes packet. If he is Part P then his registering body will have a technical helpline and he should phone them.(no disrespect to A.Lee who actually does take an interest in his electrics)

Such an easy solution (assuming that you cannot use a C Type MCB).

I was going to say that you cannot be a k*****ad as you use uk.d-i-y, but then I remembered so does dennis:-)

email me and I'll give you my telephone number. I'll explain the MCB options to the landlord or the electrian (who is clearly out of his depth)

[Tim..]

14A is most likely the run current. Startup current will be at least 2.5x that. Get a C type 20A breaker installed.

Tim. .

[Tim Watts]

Yes - I did the cornflake qual just to make the BCO leave me alone. There was *nothing* about breaker types, not cable types other than T+E, nor much consideration of outside work.

[ARWadsworth]

The wiki has more info than a Prat P course.

[Fredxx]

If he's a member of the NICeic, why not ask them to inspect the installation as not fit for purpose. Before you do so, make sure the wiring is up to the right CSA. A clamp meter may be hand to measure the real current taken by the machine.

[John Rumm]

One of the downsides of not having a non trip ELI tester is that the distance and resistance method is often easier!

[R D S]

It's OK. After a discussion with the landlord I doubt the electrician will be getting any more work from him. He certainly won't be getting back in our shop.

But cheers, you're a goodun.

[ARWadsworth]

Bypass the RCD:-)?

I have got to admit I do love my new tester. It has not tripped the RCD yet (other than on a RCD test). And a double check of the results show that it is quite accurate on the non trip test.

However after about 30 tests in quick succession the machine does shut down to allow it to cool.

[ARWadsworth]

Please let us know how the tripping MCB is resolved if Mr Knobhead is not coming back!.