100ms time delay rcd on main domestic unit?g

[cmp260]

my house has 100ms time delay rcd main switch. why would this have been installed in a house? is it legal?
thanks

 

[richy3333]

they were cheapest quote,

Says it all really. Buy cheap, buy twice.

It's the usual drip fed, half baked stories. The OP should tell all, or say nothing.

 

[cmp260]

ok, i know this is not true test but just to stir it up, ive just stuck my multimeter neg in the earth prong of a scoket and other side to kitchen tap,: 4.5 ohms, sounds pretty connected to me and imagine you too. thats what i mean, they are taking the proverbial, ok, maybe they couldnt find the bond, but thats no reason to say its not earthed when it obviously is, right?

 

[brman]

seems strange there is no hard and fast rule on the water earth, one persons c2 is anothers c3.. can this be right?

There is no document that that states what fault is what code (there are some guidelines, but that is all they are) so it is down to the experience and common sense on what to code things as. so you can get different opinions from different sparks.

Yes, the regs state that the connections should be visible for inspection so you do not meet the regs. However is it "potentially dangerous" (C2) or "needs improvement" (c3)? that is down to judgement.
The way I judge it is on what I would do if it was my house to be happy my wife and kids are safe. So in this case, if one end was visible and it measured at less than 0.05ohm I would say that the risk of danger is low and I would give it a C3. i.e I would not rip the house apart to find the other end but I would fix it if I got the chance. Others might say that to guarantee it is safe they need to see the other end so they would give it a C2.

To be fair though, would it be that bad to cut an access panel just above the stop cock so it can be inspected? It would stop hassle every few years when you need another inspection.....

 

[brman]

ok, i know this is not true test but just to stir it up, ive just stuck my multimeter neg in the earth prong of a scoket and other side to kitchen tap,: 4.5 ohms, sounds pretty connected to me and imagine you too. thats what i mean, they are taking the proverbial, ok, maybe they couldnt find the bond, but thats no reason to say its not earthed when it obviously is, right?

no. 4.5 ohms is way too high. Needs to be less than 0.05 ohms and you won't test that with a standard multimeter! I thought you said it measured at 0 ohms?

 

[trev]

ok, i know this is not true test but just to stir it up, ive just stuck my multimeter neg in the earth prong of a scoket

Please stop poking things in sockets mate.

 

[Octopus]

sorry what is Zs? you could be right ive read it wrong as 25 "?)

Included in your EICR will be a table of test results.... Against each and every breaker/fuse/MCB there will be a series of numbers stated......Zs is probably named as "earth fault loop impedence) and should be over to the right and is a live test.

 

[cmp260]

ok thanks brman, ill rip up the stopcock cover tomorrow

 

[Steve_P]

And when all's said and done, the only thing (apart from the 2 circuits with the high Zs which need investigating) that doesn't look like a quick fix is the bonding.

Ok, I'll stick my neck out here. Based purely on what you've told us which isn't everything, without being on site and taking into account quite a other few factors. Yeah, I reckon the EICR has quite probably and rightly failed. So what? The remedial work that you describe isn't that much, even the bonding can probably be found quickly enough. The 2 circuits with the high Ze could be anything but what have these people been paid so far? A days labour? And at the cheapest quote that's probably less that 100 quid. So they tell you that some stuff needs to be sorted to make it safe? I would have to agree.

TBH, I reckon we're going round in circles with this but if you want to keep thrashing it out, it's without my input.

 

[Octopus]

He did say he went for the cheapest quote so the bloke was probably only there for a couple of hours

I'd like to see the Zs figures (hint, hint, see my post #46)

 

[Des 56]

ok, i know this is not true test but just to stir it up, ive just stuck my multimeter neg in the earth prong of a scoket and other side to kitchen tap,: 4.5 ohms, sounds pretty connected to me and imagine you too. thats what i mean, they are taking the proverbial, ok, maybe they couldnt find the bond, but that is no reason to say its not earthed when it obviously is, right?

There you go then,if your happy with that,it is your call
There is obviously more involved in testing and interpretation of results than you are aware of

The spark was there to report on the installation not to carry out remedial works,so critism of why he didn't disconnect and alter mcbs is unfair on that spark

 

[brman]

ok thanks brman, ill rip up the stopcock cover tomorrow

Sounds a good plan.
And, now I think I understand it a bit better I think you could do worse than get a quote from the guy that did the EICR to sort out the high Zs and disconnect the unused ccts. If he was cheap on the EICR he might end up being cheap for the remedial and I am starting to think he might actually have done a good job on the EICR............

 

[cmp260]

steve, youre right its rightly failed on some aspects, but wtf does high impedance on 25 on circuits 2 and 3 mean?

 

[cmp260]

and he did fail it for having a 100 ms td main, why?

 

[Octopus]

steve, youre right its rightly failed on some aspects, but wtf does high impedance on 25 on circuits 2 and 3 mean?

FOR GODS SAKE MAN get the EICR out and list the readings you've been given on here - or hasn't he given you a full report??

 

[cmp260]

ok dude, chill out, its a lot of typing and i cant attach it, hang on ill make a dropbox link

 

[trev]

steve, youre right its rightly failed on some aspects, but wtf does high impedance on 25 on circuits 2 and 3 mean?

I have no idea what that means but why don't you ring the guy tomorrow and ask him. It could be that he had a slight brain fart.

A word to the wide though, don't tell him you've been asking questions on here. He would probably be offended, I know I would

 

[Octopus]

ok dude, chill out, its a lot of typing and i cant attach it, hang on ill make a dropbox link

Try Cooker circuit 40A MCB type then the earth fault loop reading

eg. 40A BS60898 0.89

 

[cmp260]

heres the doc. i did ring him on fri and asked him, he said hed get back, but hasnt..

hers thendoc http://db.tt/a09WQgKS
cheers

 

[cmp260]

trev, thanks for the advice, and i know wha t you mean, but how would you suggest i tell him that a 100ms td is not a fail?

 

[trev]

trev, thanks for the advice, and i know wha t you mean, but how would you suggest i tell him that a 100ms td is not a fail?

Simple, you don't. You could ask him why it's a fail though. Seriously, just ring him and ask him to talk you through the report, I'm surprised he didn't do that anyway. It's something I do as a matter of course because my clients, like you, are not electricians. If they were they wouldn't need me.
Call him up, get him to talk you through everything and tell him to explain it in layman's terms. jobs a goodun mate(hopefully)