Electrical - Removing the Company Fuse

[Cursitor Doom]

Greetings, gentlemen,

I was jet washing the motor today when all of a sudden, the power cut out. A few cursory checks revealed the culprit to be the main RCD next to the electricity meter. It's been a pain in the arse for years with nuisance trips. Lightning strikes nearby: it trips out. You sneeze: it trips out. And sometimes even if you don't sneeze or fart too loud, it trips out for no apparent reason. I found the damn thing would not reset this time. After removing the only possible cause for a trip, the jet-washer, it still would not reset. I had my own personal power cut. I called the power company and they said, "nothing to do with us, mate. We're only responsible up to the meter." I said, "Right, so that RCD is not your property, then?" "Correct", they replied. "So you don't mind if I remove it? "Go right ahead, it's not anything to do with us." "In that case, do I have your permission to remove your 100A fuse?" "No! Absolutely not!" "What am I supposed to do, then?" "Call an electrician. He will need to submit a request to us by filling out a form. It's on our web site somewhere." "Look, I can't hang about waiting for an electrician to turn up and then have him go through that rigmarole. I've got a freezer that's defrosting, no hot water and I'm dirty, smelly and need a shower." "Sorry, can't be done. Call an electrician." So that was that. They were implacable about me taking their fuse out. So I had no choice, I had to bypass the RCD whilst the supply was still live. Here's my effort. It's not pretty but it got me out of trouble today:

I'm just wondering about a couple of things:

1). What would they have done if I'd broken the seal and removed their fuse? 2). I want to take the opportunity to do an earth loop impedance test whilst that sucker is bypassed. Why don't these devices have a bypass switch so you can do this safely? The bloke at the electrical supplies shop told me he'd never seen one with a bypass switch. WTF not? Surely some fucker must make one?

Cheers, CD.

[Roger Mills]

I wouldn't have asked - I'd have just done it! It's not like you're bypassing the meter. If you ask him nicely, Adam will fix you up with some new seals.

Is the RCD between the meter and the consumer unit? Bad idea if it is - it's much better to have ultiple RCDs each with just some of the circuits in the CU rather than having an all or nothing whole-house RCD.

Your bypass cables look worrying to be. What size and spec are they. They look to me like cables intended for 12v circuits on cars rather than mains, and don't look anywhere near thick enough. If the RCD trips when you're using a lot of load, you could have a fire on your hands!

[Chris Green]

Absolutely nothing. I took my main fuse out about 20 years ago and the seal still hasn't been replaced.

[Cursitor Doom]

I doubt they'd look the same as these.

Both! The duff RCD by the meter plus individual ones in the CU.

Yup, totally inappropriate and out of a car. Just a temporary expedient til I fit the new RCD. I will not be drawing much current through it until the new one's in situ. I'm still mystified by the lack of a bypass switch on the duff RCD - and any of the new ones on the market. :-/

[David Wade]

Its called idiot proofing. Folks would by-pass the thing all the time....

Dave

[alan_m]

When my meters were replaced, no paper (warning) seal and the wired seal is anonymous. It's a plain seal with no company etc. markings from crimping tool.

I'll bet these days that depending on which contractor replaces or works on the main fuse all the sealing will be widely varied in an area and a replacement Ebay wired and crimped seal would never look out of place. A pair of pliers can be used on many seals to crimp.

If questioned (highly unlikely) - "it was like that when I moved in to the property".

[alan_m]

... rather than actually fixing a potentially dangerous problem.

[alan_m]

+1 I actually replaced a seal myself when I removed the main fuse and it looked no different to the seal that was used when the meters were latter changed and an isolation switch fitted.

[SH]

If your CU is already stuffed with RCDs (I read the rest of the thread) then I should think you could replace that Wylex RCD with a switch fuse like below:

I would also consider using a Henley Block as you have two sets of cables coming out of that old Wylex Switch fuse, particularly as the two sets of tails are of different diameters

See

[Mike Clarke]

No need for an extra fuse, just need a 100A isolator switch.

[SH]

Totally agreed with provided the tails between meter and CU are less than 3m long :-)

[charles]

I've just looked my meter/cut out. There is no seal on theLive fuse, but there is one on the neutral terminal. This was a result of a smart meter installation - probably 4 years ago.

[Roger Mills]

In that case, the first RCD is redundant. Just replace it with a Henley block or isolation switch.

Whether you pull the company fuse or do it live is up to you.

[John Rumm]

[snip]

Nothing - they would not know. If they knew, then also nothing unless you also did something that somehow affected the rest of the network, like short out the supply to the property!

With modern test gear you can do an ELI test without tripping the RCD. Having a switch would be counter productive for several reasons: more cost, less reliability, and chances are it would be used by the less clued up to "fix" nuisance tripping problems by in effect permanently disabling earth fault protection.

Never seen one...

ISTM that if you particularly wanted something like that you would wire a bridge across it with a suitably rated "main switch".

15th Edition "whole house" RCDs are deprecated anyway because of the nuisance trip problem, and lack of fault discrimination that you get as a result. In some cases they can make for a less safe installation.

If I were faced with the situation you are in I would pull the main fuse and replace the RCD with with a 100A dual pole isolator in a suitable enclosure. e.g. like that pictured here:

Does you CU have proper RCD protection included? If not, then that would be the next job :-)

[Jack Harry Teesdale]

Probably not a lot but the call you made would have been logged and if anything untoward resulted from your actions i.e a fire or injury to one of their employees, you might be in deep doo do.

A by-pass switch is not a good idea.

>

[alan_m]

Just remember the bit you can take off is the output side.

[Cursitor Doom]

Dangit! I never should have asked in the first place, clearly. Fucked it for myself on this one.

That did occur to me some time later. They could use a meter which tests using << 30mA and there's no bypass needed. Thanks for the confirmation.

Not a bad idea there, John.

Thanks, John. You're the voice of reason here with all things electric. I'll adopt your suggestion accordingly....

[Clive Arthur]

<snip>

My dad did something similar live. He wasn't particularly bothered about getting a shock, but the white-hot ball of molten screwdriver shaft caught him rather by surprise.

[Cursitor Doom]

I'd really, really prefer not to do it live. There's only a 100A fuse between me and the substation and if you've ever had an arc-flash - as I have back in 1984 - it's not something you're ever going to forget. Awful lot of energy potential there waiting to give you a bad day. :-(

[John Rumm]

Not really - you could still do it. If anyone ever asks "the electrician did it"!

Yup, that or very short duration pulsed tests to stop the RCD from responding.

Well as always, allow for the possibility my having of a brain fart or more general talking bollocks :-)