hook up problems with RCD tripping

[janieh]

Hello

I'm having some problems with my hookup in the van tripping constantly. It's really annoying as I thought we had it sorted! This was a previous problem and we got an electrician out who tested all the equipment and said there were no faults. He tightened all the wires he could get access to and that seemed to solve the problem. It did happen again a couple of times but in the main has been fine since last July.

However, we went away this week and it was tripping every 15 minutes or so. The electrician had suggested that if it happened again that we should try replacing the RCD as they can just go wrong when they're old. Has anyone replaced one of these themselves? and if so were did you source it from? the ones I've found on the internet have all been quite big, and the space we have to fit ours in is quite small.

I've uploaded a few photos here: https://picasaweb.google.com/jane.herse ... directlink

Any ideas welcome!
Thanks, J

[BOXY]

Try "City Electrical Factors". Google shows up a few near Brixton. Once you've got a new RCD it's a simple job to swap the over, but as its 240v you might want to ask a friendly sparkie to do it for you just to be sure.

[1664]

I seem to recall a thread several years ago regarding the westy RCD. If I remember correctly, you might find that it's not a 'bog standard' design/size so obtaining one that is a straight swap might prove problematic.

Hopefully I'm wrong..............

Did the electrician test the RCD as well as the wiring? Does it happen only when using certain equipment or is it entirely random tripping?

[janieh]

Try "City Electrical Factors". Google shows up a few near Brixton. Once you've got a new RCD it's a simple job to swap the over, but as its 240v you might want to ask a friendly sparkie to do it for you just to be sure.

Thanks, I'll have a look at their site. I'll certainly get an electrician to do the work as I don't trust my own diy skills with electricity!

[janieh]

I seem to recall a thread several years ago regarding the westy RCD. If I remember correctly, you might find that it's not a 'bog standard' design/size so obtaining one that is a straight swap might prove problematic.

Hopefully I'm wrong..............

Did the electrician test the RCD as well as the wiring? Does it happen only when using certain equipment or is it entirely random tripping?

Yes I think I found something to that effect last time I investigated. I'll search the forums again. I can't remember if he actually tested the RCD, I've got the paperwork somewhere. He checked the fridge and laptop we'd been using. It trips out randomly, sometimes when the laptop's on, sometimes just the fridge or sometimes just a light. It even tripped when we didn't think we had anything running off the mains.

Cheers
J

[1664]

If he tested the RCD he'll (should) have done a 'half' test (15mA for a 30mA trip RCD). If that tripped it, it would definately be faulty - mind you, he'd have mentioned it if he had I suppose. I was rather hoping it was caused by a specific piece of equipment like the laptop instead of the actual RCD itself.
Why not ask your electrician if he can 'temporarily' wire another RCD (if he's got a spare knocking about) in it's place and see if that trips with the hook up energised - if it did then the problem would lie with something other than the RCD.

[janieh]

Hi All

Just thought I'd update you. We dismantled the RCD and took it to City Electricals to find a replacement. They took one look at it and said 'that looks old, don't think we have anything like that'. However, after a bit of pestering and asking what would do the same job someone who had a better idea what he was talking about came and had a look at it!

He said it was actually dangerous - as the RCD was 100mA that wouldn't actually be good enough to stop the shock damaging your heart - he said they are now 30mA. So it was worth replacing anyway. Basically, once you've dismantled the metal casing holding the RCD the bits inside are quite standard - they are hooked onto a rail in a similar way to those in a large household consumer unit. So we were able to get the smallest RCD he had, and a bit of blanking plastic and since we had an electrician working in the house this week we got him to install it. We've now tested it while hooked up to the household power and it seems to be working and not tripping.

So hurray! thanks for all the help. We need a trip away to double check but so far, so good.
cheers
Jane

[1664]

So are standard Westy RCD's 100mA then? I've never looked that close.....

[1664]

Just had a closer look at you original photos of the unit. It states 0.01A which is 10mA not 100mA so perfectly safe......

https://picasaweb.google.com/jane.herse ... 1150722706" onclick="window.open(this.href);return false;

incidentally, if your sparkie hadn't noticed it was only a 10mA unit and half tested it as a 30mA it would have tripped it........

[kevtherev]

That's no sparky in my book... mistake made

[1664]

That's no sparky in my book... mistake made

well we don't actually know he missed it Kev, may have tested at 10mA and it still failed. I'd probably have automatically set the meter to 30mA (as that's the 'norm' in campers) and I'd only have checked the rating following a 'fail' on 1/2 test. Now I know Westys are 10mA I've learnt something (else)

unless you're referring to the wholesaler for saying 100mA??

[kevtherev]

No the sparks.. I would have tested it for trip, as that was the problem... and I'm not a qualified electrician

[1664]

You should test at 1/2 the rated 'trip' value (which shouldn't trip it), the actual 'trip' value (which should trip it), 5 times the rated 'trip' value (which should still trip it, but a lot faster), then the 'TEST' button. (Them's the rules for 30mA anyway) Some tester can do a 'ramp' test which gradually increases the fault current until it trips, which is a handy function as it tells you the exact mA value that trips it.

[kevtherev]

would a ramp test tell you more about the culprit?

[1664]

Only if the culprit was the RCD. Won't tell you anything about the wiring or what's plugged into it. Trouble with RCDs are they're so damn sensitive - a 10mA one especially so. I'd expect a typical 30mA one to trip in the 26-28mA kind of range. Can't really comment on 10mA ones as they are pretty rare (in my experience); probably reserved for especially sensitive installations/environments such as operating theatres and the like, at a guess.....

In order to pass a test, not only do they have to trip at their rated value, but they also have to trip within strict time limits as well (milliseconds)