Consumer units

[Maxxy]

Hey all. Right, went round a mums friends house the other day because her RCD keeps tripping 2 to 3 times a day.

So i figured i would go and have a look, see if theres an obvious solution, which there wasnt.

My next advice to her was going to be to get an approved electrician to fit a new Consumer unit without RCD protection, and change the sockets near the front and back door so they are RCD protected. The power shower can be fitted with an RCCBO.

Is this good advice, or are all domestic houses meant to have all sockets on RCD's these days?

Theres no point me advising her to get someone in to do this if its not allowed!

 

[securespark]

That's within reg, but you must label all inappropriate sockets as such.....Bit of a fag.

 

[DESL]

Firstly you do not need a new consumer unit

You have a fault somewhere

Appliance
Fixed wiring
or RCD

So you need to eliminate each in turn starting by asking you Mums friend if there is an appliance she's using when RCD trips. Kettle, iron, shower etc

if not then un plug all appliances and see if RCD keeps tripping.
Then if RCD doesn't trip you need to check all the appliances before you plug them in

If RCD keeps tripping time to get a sparky in as he/she will be able to locate fault in fixed wiring and also check reliability of RCD

 

[JohnD]

Sockets that can reasonably be expected to be used with equipment outside should be on an RCD. So should electric showers.
IMO all sockets should be RCD protected.

You are on the wrong track, faced with an earth fault, to want to remove the protection that cuts the power when it occurs. You should be trying to find the fault and fix it.

It is usually a watery appliance like a washing machine, kettle, immersion heater or shower. Electric irons are the only thing that ever does it in my house. Sometimes an outdoor circuit that is getting wet from rain. Sometimes an electric oven element that is breaking down. Sometimes mice gnawing the cables. You can start by unplugging suspect appliances and see if the fault stops. If you get a little RCD adaptor as is used with lawnmowers, and plug in suspect appliances through that, it will usually trip faster than a house RCD.

What make of CU is it? RCBOs are far preferable to a single RCD, as they don't cut off the other circuits when a fault occurs on one.

edited, bah, too slow

 

[Maxxy]

Cheers for the feedback. Yeah ive been through everything.

Ok, more detail - pretty dull!

She had her boiler serviced, and most bits in it replaced. Apparently the PCB is more powerful, so this is probably whats causing the problem. I figured i could find what else is causing problems in the house, and reduce them, so that the boiler would not keep tripping the RCD.

So..i went round there, and quizzed her on when it happens etc. To my mind, theres no logical reason. She always unplugs everything when its not in use, and when i turned up only the telly was plugged in and on. I used a clamp meter, and the earth leakage was around/less then 10 mA

she turned the boiler on - lots of clanking as the fan is now buggered from the continual tripping out of the RCD, and the earth leakage was moving between 10 and 20 mA

She turned the boiler on and off a few times while i was there, and it didnt trip out the RCD

The RCD also trips when shes out of the house, aka no other appliances are even plugged in.

The only thing i could narrow it down to having an impact was the outside light - which she confirmed used to trip the RCD when it was used, so i turned the breaker for it off.

I considered replacing the RCD incase it was faulty, but further reading indicated these rarely have faults, and it would cost 90 quid to buy a new one - more than it would cost to buy an entire consumer unit with one fitted!

I'll be phoning her tonight to see if isolating the outside light has solved the problem, but im not holding out any hope.

The only solution i can see is to remove the RCD (i wont be doing this as im not registered with a scheme).

It may cost her a few hundred quid getting a new board fitted, and the sockets changed, but its cheaper than forking out a few grand for a new boiler, which may still have the same problem!

 

[Maxxy]

Firstly you do not need a new consumer unit

You have a fault somewhere

Appliance
Fixed wiring
or RCD

So you need to eliminate each in turn starting by asking you Mums friend if there is an appliance she's using when RCD trips. Kettle, iron, shower etc

if not then un plug all appliances and see if RCD keeps tripping.
Then if RCD doesn't trip you need to check all the appliances before you plug them in

If RCD keeps tripping time to get a sparky in as he/she will be able to locate fault in fixed wiring and also check reliability of RCD

Done all the above. All appliances are always unplugged when not in use. Should have mentioned that the boiler had been serviced in my original post though.

I am a sparky, but my domestic knowledge is limited, hence the fact i didnt mind having a look for the problem if it was something simple, but told her she may have to get someone else in to fix it, even if it is something simple as i may not legally be able to do it.

The RCD didnt trip while i was there. It seems to just be a combination of small earth leakages building up to trip it.

 

[Maxxy]

Sockets that can reasonably be expected to be used with equipment outside should be on an RCD. So should electric showers.
IMO all sockets should be RCD protected.

You are on the wrong track, faced with an earth fault, to want to remove the protection that cuts the power when it occurs. You should be trying to find the fault and fix it.

It is usually a watery appliance like a washing machine, kettle, immersion heater or shower. Electric irons are the only thing that ever does it in my house. Sometimes an outdoor circuit that is getting wet from rain. Sometimes an electric oven element that is breaking down. Sometimes mice gnawing the cables. You can start by unplugging suspect appliances and see if the fault stops. If you get a little RCD adaptor as is used with lawnmowers, and plug in suspect appliances through that, it will usually trip faster than a house RCD.

What make of CU is it? RCBOs are far preferable to a single RCD, as they don't cut off the other circuits when a fault occurs on one.

edited, bah, too slow

Its a mem board, so mem 100A 30mA RCD. upstairs and downstairs ring, plus the outside light, plus the electri shower run throguh the RCD.

I went through all your bits, but to no avail. The kitchen is on its own seperate circuit, not on the RCD side. I told her its most likely to be the kettle/toaster/iron etc etc, but the tripping happens sometimes when shes out of the house, nothing plugged in.

 

[JohnD]

On the outside lamp - it may be an N-E fault, so turning off the MCB may not be enough.

I assume the boiler is on an FCU so the idea of the Gardener's RCD Adaptor may not help. You can buy an RCD FCU but they are in the £20-£30 range so a bit dear for a guess.

I believe boilers most often trip RCDs when they have a water leak touching the electrics. This can be onto the PCB but is often on the pump. Sometimes if you have a look you may see water stains.

p.s. Is it a Memera 2000 board, or the old 21 or "Q" type? Does the RCD have the lever that you partially rotate to reset? (If you switch on the "email" on your profile I may be able to help

 

[Maxxy]

Yeah its the 2000 model. Doing the email thing now, cheers

RE the outside lamp though, its been there for a few years, so it cant be a N-E fault, or it would have kept tripping the RCD since it was installed.

I figured it might be water getting into the lamp, but didnt think about the fact just turning the mcb off wont help. I'll sort that next time i pop round there