power trips in garage

[cliff1010]

I live on a farm we have normal fuse box in the house RCB's etc and a separate supply to out buildings this feeds into the stable where it goes to another fuse box split to sockets and lights. It also supplies the garage ( another fuse box). The RCB in the house for the outside supply keeps tripping. I have unplugged everything and re set turning the lights on it will trip straight away re set trip and use 2 of the 3 plug sockets it trips again but one socket nearest the fuse box is fine not tripping. I would call an electrician after the Xmas holiday but my freezer is on or was now de frosted.

I am confused is it normal for both sockets and lights to trip an RCB ?
Anyone any suggestions where I should look for a fault first.

Although I don't know all the terminology I am not daft and take the right precautions. So am happy to check things out in the hope of curing the problem.

Cliff

 

[PrenticeBoyofDerry]

It is normal for the RCD to take out the circuits it is protecting, so if sockets and lights are covered by the same RCD an earth leakage fault in either of those circuits would trip the RCD, therefore powerloss to both circuits and any other circuits also on the same RCD.
Best method for fault finding would be to unplug all loads on the RCD, then introduce one at a time and see if you can then put it down to an appliance fault, also if you could disconnect lights that would help but unplug first, that means removing the plug not switching off at socket as you can still get an earth neutral fault with plug in.

 

[sparkwright]

By RCB, do you mean MCB, or RCD (also known as RCCB)?

This makes a difference in diagnosing your fault.

Write down exactly what is printed on the item(s) that trip.

RCDs can detect can make it seem a fault is on more than one circuit, when very often it isn't.

Photos and a better description of what's happening would be very welcome.

 

[knowall]

Water ingress

KA

 

[knowall]

1. Switch off BOTH main switches in the out buildings, reset RCD in house. If it trips the supply cable to the outbuildings may be damaged.
2. If it resets switch on one board at a time obviously the faulty "building" will become evident, then break down your fault finding from there.

Regards,

KA

 

[PrenticeBoyofDerry]

It will be beneficial to eliminate circuits, to nail down which is causing the problem, if the RCD is tripping regardless of what load is on/off.
I would suggest opening the MCB (off) of the socket circuit, then removing the neutral of this circuit from the busbar, then see if this stops the RCD tripping.
If doesn't reconnect neutrals, close breaker and then open the light breaker remove that neutral and see if RCD trips.
Before removing covers of consumer unit, isolate the board and keep isolated whilst removing neutrals.

 

[cliff1010]

HI I have taken a photo of the supply in the house before it goes outside

Untitled

• cliff1010
• 21 Dec 2013
• 1

it's the smaller trip on the right that trips.

it's difficult to trace as I reset and can switch the light on in the stable and it trips and also reset and switch the light on in the garage and it trips.

If it's water ingress how do you fix that apart from the dry it out answer someone will say. I think it must be that as the previous owner wired in extra strip lights in the garage and these were not sealed, just wires in a block ( I removed this earlier and took out two strip lights from the system)

The fuse boxes in the other building are the old type with cartridge fuses.

Cliff

 

[cliff1010]

happy to take photos of the other parts tomorrow.

 

[PrenticeBoyofDerry]

It's an MCB then.
So the MCB stays on until you put a load on the lights or a load on the sockets. Are both of these circuits individually protected at the distribution board in garage?

 

[Adam_151]

Are you absolutely sure its the small device on the right thats tripping?

If it were the RCD (larger on the left) that was tripping then it sounds like a classic neutral earth fault

if its deffinatly the device you say, then I'd be quite supprised, and the advice below probably isn't that usful to you

Does the fuseboard in the stable need to be on to be able to have power in the garage? If not then try it with one fuseboard switched off at a time to see if the faults in the stable or garage. If you do need the stable board on to get anything in the garage, then switch the garage board off and see if you can use power in the stable without tripping it out.

If you have a radial socket circuit and plugging the same appliance into the first socket doesn't trip it, but sockets further down the line do, then I'd expect the fault to be on that circuit (is there a fused spur for an outisde light on that circuit)

 

[cliff1010]

Adam, you are right it's the bigger one on the left that trips.

I have switched off the fuse board in the stable and the garage still has power. I have turned the lights on in the stable they work as does the single plug socket. So we can rule out the stable.

The garage:
I have 3 plug sockets and only the first one closest to the fuse box works.
the other two even plugging something in will not work or trip the mcb

the only thing to trip the system is when I turn on the lights.

I don't have any external lights on the circuit.

 

[cliff1010]

I have now taken some photos in the garage ( before I am shot down for shoddy work these are not my electrics all inherited ) yes should have re wired them in the summer but no time but great now a few days before Christmas

//www.diynot.com/network/cliff1010/albums/

you will see in one photo he has used a block and just wired in this one I have removed from the circuit. the junction box I added yesterday as the mess of wires was as the block. the system was tripping before I did this.

just confused as to why I have lost some power in sockets and not in others.
+ any ideas on the lights do I strip this back to one light ( remove all others ) and then add one at a time ? he seems to have added lights as spurs. all confusing.

Cliff

 

[PrenticeBoyofDerry]

I have switched off the fuse board in the stable and the garage still has power. I have turned the lights on in the stable they work as does the single plug socket. So we can rule out the stable.

If you have isolated the stable supply, how can the stable lights work and how could this eliminate the stable?

The garage:
I have 3 plug sockets and only the first one closest to the fuse box works.
the other two even plugging something in will not work or trip the mcb

so you would need to check for loose connection within socket back boxes, then the power maybe able to be restored, providing they are connected to each other? They may also be a fused connection that is part of the circuit, where the fuse has blown.

the only thing to trip the system is when I turn on the lights.
I don't have any external lights on the circuit.

So that is where you need to investigate, RCD can be very sensitive.
So what type of lighting is on this circuit, do they all switch from the same position or are they individually switched.
It could be a moisture issue, if water has ingressed or high condensation issues, also loose connections, any damaged cables, mechanically or rodents. I would do a little investigation in to the condition of the cables, faulty fittings, loose connections etc...
Fluorescent tube fittings, commonly when faulty, trip the RCD

 

[cliff1010]

hi in answer to the questions I eliminated the stable as everything works.
Yes understand it didn't at one point so will check for loose cables etc..

no fuses have blown the main trip tripped, good point I will open up the two remaining sockets and check for loose connections.

The lights are all strip lights and come on with one switch

I have about an hour before it gets dark so will check as much as possible

Cliff

 

[PrenticeBoyofDerry]

no fuses have blown the main trip tripped, good point I will open up the two remaining sockets and check for loose connections.

Did these socket work previously ever? There could still be an in-line fuse connection, this has nothing to do with the trip switches at the board.
It's generally a square accessory similar size to a single socket outlet/switch plate which contains a standard plug type fuse, if the two sockets are protected by one and the fuse has blown or even could be a switched version where the switch has been opened. The power will be lost.
Remember to isolate the circuit prior to removing covers and prove all cables within the backboxes are dead.

The lights are all strip lights and come on with one switch

I have about an hour before it gets dark so will check as much as possible

I would suggest that you have at least one faulty fitting then, you would need to link these out, one by one to eliminate which are good and which are not.
The procedure to do this would depend on the method they are connected, it maybe that they are all looped in at the terminals at the fittings or possibly via junction boxes. But it is likely you will either have two sets of cables or one set of cables at the fittings, if you disconnect the live/lives, neutral/neutrals and earth/earths, put the cables together as they were on the fitting in a terminal block/connector, this will disconnect that particular light from the circuit, then it's a case of eliminating the fitting/fittings that are causing the RCD to trip.
Take a note of the connection prior to disconnecting, so they can be reconnected identically. Again isolate and prove dead, prior to removing covers and becoming in contact with conductors.