Garden cabin tripping fuse in house

Del007 · 21-06-2022 8:41pm #1

We recently got a cabin built out in the garden. The cabin itself has a fuse board inside which is connected to my fuse board in my house.

It has tripped the cabin's fuse in the house fuse board a number of times. It has been raining all of these times.

None of the mcb's in the cabin have ever tripped.

I had the electrician out today who thinks that there could be a problem with moisture getting in contact with the lights.

Shouldn't the mcb's in the cabin trip before the fuse in the house trips?

Thanks for your help/advise

kirk. · 21-06-2022 9:18pm

New electrician

Sorry but I mean cabins are not complicated

Probably some cockup in the wiring or wired it off the main RCD

Either way get someone else

kirk. · 21-06-2022 9:22pm

Your last point ya the cabin should trip first not the house

Electrical ABCs:

1) You don't create an unnecessary hazard or nuisance

2) Connect swa to an MCB or fuse if that's whats even supplying the cabin

meercat · 22-06-2022 6:30am

https://www.boards.ie/discussion/2058251222/garden-cabin-tripping-fuse-in-house

If the cabin is wired correctly then The problem most likely is on the cable between the house distribution board and the cabin distribution board or perhaps the tripswitch is overloaded. Is the tripswitch in the house distribution board a rcbo(post photos)Either way it should be a simple diagnosis from a competent rec with the right equipment.

Del007 · 22-06-2022 7:17am

The cabin is def not overloaded. It has 6 downlights and all that's plugged in is an Amazon speaker/ a modem and a heater.

It has tripped when no lights were turned on, would this eliminate the lights?

The cabin is wired with a 4sq swa cable.

asdfg87 · 22-06-2022 7:29am

https://www.boards.ie/discussion/2058251222/garden-cabin-tripping-fuse-in-house

I expect its moisture getting in the cable thats feeding the shed, the trip will work back from the problem.

What type of cable is going from house to shed?

Del007 · 22-06-2022 7:44am

It's a 4sq swa

Bass Reeves · 22-06-2022 7:51am

https://www.boards.ie/discussion/comment/119233459#Comment_119233459

Is there a joint on the SWA between the house and the cabin. This may have happened where the SWA was previously put in for outside services

b318isp · 22-06-2022 7:53am

Get a REC to megger the feed cable to the shed. This will check the supply cable for damage or water ingress.

Del007 · 22-06-2022 7:58am

https://www.boards.ie/discussion/comment/119233465#Comment_119233465

It's a new cable that was put in, there's no breaks in the cable

Del007 · 22-06-2022 8:03am

https://www.boards.ie/discussion/comment/119233469#Comment_119233469

The electrician was out yesterday, I'm not sure why he didn't do this.

He seems adamant that the problems are with the lights, he did say that some of them had signs of corrosion on the cables and fittings themselves.

I still don't understand why the MCB in the cabin wouldn't trip first if this was the case. It happened at night time when there were no lights on.

Bass Reeves · 22-06-2022 8:15am

I presume he put an new earth bar in for the shed??

Del007 · 22-06-2022 8:20am

https://www.boards.ie/discussion/comment/119233537#Comment_119233537

I really don't know if he did or not

meercat · 22-06-2022 10:04am

https://www.boards.ie/discussion/comment/119233537#Comment_119233537

It’s not a requirement or necessary

OP ,did you Get a certificate for the electrical installation to the cabin

Del007 · 22-06-2022 10:38am

The cabin was build by a separate company. The builders of the cabin also wired the cabin. His electrician wired the fuse board but the workers did the terminations in the sockets and lights

I got my own electrician to run a cable out to the cabin. He is a qualified electrician. He also did tests on the cabin as he said that he wouldn't sign it off otherwise. He then gave me a cert for it. He did mention something about the lights but I'll have to have a look at the cert to see what it says

Del007 · 22-06-2022 11:00am

It says on the cert that there are no junction boxes for the connections at the downlights and that they are to be installed at a later date

kirk. · 22-06-2022 11:02am

Have u got a pic of the board in the cabin

Del007 · 22-06-2022 11:10am

These have never tripped

b318isp · 22-06-2022 12:36pm

https://www.boards.ie/discussion/comment/119233502#Comment_119233502

He may be not wanting to deal with a damaged underground cable!

I agree that the cabin 10A MCB should be tripping before a 32A MCB in your main board if the lights were defective, assuming the "Shed" MCB is not fed by the house RCD (note that recent ET10101 wiring regs changes require RCD protection on light circuits for installs since ~2020).

Del007 · 22-06-2022 12:48pm

The SWA cable is in a conduit running along the wall, there's no way it could be damaged

meercat · 22-06-2022 1:09pm

https://www.boards.ie/discussion/comment/119234267#Comment_119234267

No rcd protection light circuits

no surge protection (or documentation it’s not required)

no double pole isolation distribution board

surprised anyone certified that

smuggler.ie · 22-06-2022 1:18pm

Would it be normal to have 80A rated "main isolator" in the cabin vs 32A rated breaker on main fuse board as per images posted above?

Del007 · 22-06-2022 1:27pm

https://www.boards.ie/discussion/comment/119234797#Comment_119234797

Where does this leave me now? Not sure what to do now

Del007 · 22-06-2022 1:35pm

https://www.boards.ie/discussion/comment/119234862#Comment_119234862

I'm also confused by this, shouldn't the breaker in the cabin be less than the breaker in the house?

Tow · 22-06-2022 2:36pm

https://www.boards.ie/discussion/comment/119234862#Comment_119234862

The Mains Isolator is a switch, not MCB. Would it be possible for 'neighbours' to plug anything into the outside sockets?

The next easiest step is to switch off circuits in the shed to try and isolate circuit the issue is on. Or get electrician to megger them... It is hard to see the 10amp lighting circuit tripping the 32amp Mcb in the house and it's own MCB not tripping.

Del007 · 22-06-2022 2:48pm

My neighbour is an 82 year old woman, I doubt it :)

It seems to have been raining everytime that it has tripped, I can't be 100% certain as it tripped a few times over night. In total it has happened 6 or 7 times

zg3409 · 22-06-2022 2:55pm

The electrician needs to diagnose and fix the issue.

I would not try a DIY diagnosis.

It could be a faulty breaker, it could be damaged cabling (even in a conduit or with no visible damage on cable. It could be water getting in lights.

Really someone needs to use the proper tools to check the issue. Any suspect breakers should be replaced to rule them out. Don't try this yourself as there is various breaker types and you seem unsure. I have seen all sorts of weird issues, but a different, good electrician should at least be able to swap out the basics and maybe isolate the lights if suspect and use a table lamp for a while. There are tools for testing the parts.

Bruthal. · 22-06-2022 4:35pm

Possible faulty breaker in house, or a fault on the cable, which can be anywhere on the cable, but usually at or close to terminations at either end (house or shed boards, JBS etc), or a fault in the shed board itself.

All asuming the lights etc in the shed are properly wired to appropriate breakers.

meercat · 22-06-2022 5:59pm

https://www.boards.ie/discussion/comment/119234921#Comment_119234921

Get the rec that certified it to come back,put everything right and recertify it. Also ask for a copy of the test records.

kirk. · 22-06-2022 6:44pm

https://www.boards.ie/discussion/comment/119235912#Comment_119235912

I would assume it's on the supply side

I wouldn't rule anything out at the cabin either

Bruthal. · 22-06-2022 6:55pm

https://www.boards.ie/discussion/comment/119236415#Comment_119236415

A safe assumption assuming its correctly wired. Parts of the shed DB will be on the supply side. Ye never know what has been done. Water into lights as a diagnosis seems a little bit like guesswork anyway. But as said, ye never know what anyone has done.

Del007 · 22-06-2022 7:07pm

https://www.boards.ie/discussion/comment/119236259#Comment_119236259

He was back yesterday and tested everything. I wasn't there so I'm not sure what type of "testing" he did.

He said that there were signs of corrosion on the light cables and fittings.

He said that the connection for the lights should have been in junction boxes.

He wants to come back and take the ceiling down to rewire the lights.

He charged me for yesterday and obviously I'll have to pay for him to come out again. I really don't want to be paying again if this won't solve the tripping issue

Bruthal. · 22-06-2022 8:55pm

Did they check the house board. See if any problem there, something else connected to shed mcb etc? Or just went looking at shed lights?

asdfg87 · 22-06-2022 9:52pm

https://www.boards.ie/discussion/comment/119234158#Comment_119234158

I would get on to the cabin supplier as the builders of the cabin wired the cabin and got an electrician to connect the board.

Not the way things are done.

kirk. · 23-06-2022 12:22pm

Looks like this cabin was wired by a committee

Once the builders are doing the wiring you're asking for trouble

You'd be checking the supply board mcb and swa cable and looking for any screwups at the cabin board anyway

Del007 · 23-06-2022 12:33pm

The cabin fuse board was wired by their electrician, the sockets and lights were done by the lads building the cabin. It was pre made in a factory and put together at my place.

The supply side was done by my electrician.

Feckin shite show :)

asdfg87 · 23-06-2022 12:38pm

https://www.boards.ie/discussion/comment/119238969#Comment_119238969

I think the people whu supplied the cabin responsible for this mess and the electrician that signed it off for them should man-up and sort this one out.

Good luck.

In the wind · 23-06-2022 12:56pm

https://www.boards.ie/discussion/comment/119234862#Comment_119234862

It's 132A on the main fuse board not 32A.

@Del007 if the electrician says it's the absence of light JB's then I'd be getting on to the Cabin supliers to rectify the situation.

Antenna · 23-06-2022 1:04pm

https://www.boards.ie/discussion/comment/119239115#Comment_119239115

It is 32A. the "132A" is part of the Hager part number (MBN132A), confusingly to those unfamiliar, only the last 2 digits being the current, the preceding digit 1 indicating 1 pole (as with single phase).

(Why not perhaps "MBN1P32A" ???)

Doolittle51 · 24-06-2022 8:36am

https://www.boards.ie/discussion/comment/119239115#Comment_119239115

There's no such thing as 132A MCB and you'd rarely find anything rated above 100A in a domestic setting.

helimachoptor · 24-06-2022 8:50am

fwiw, i have a 25sqm cabin, 4 double sockets, 8 downlights, 2 external lights.

There's a 60metre run from the board in the house, but its a 10sq cable, cabin has been in two years and not tripped.

asdfg87 · 25-06-2022 4:45pm

https://www.boards.ie/discussion/comment/119242323#Comment_119242323

Its really things with heating elements that need electric current. Whats plugged to the sockets?

helimachoptor · 25-06-2022 4:52pm

https://www.boards.ie/discussion/comment/119248901#Comment_119248901

Wife has two heaters in winter 😂 oil heater and a 2000w fan heater, then laptops, screens, lights on, fridge

asdfg87 · 25-06-2022 5:05pm

Thats what i mean if everything on at same time likely max draw about 4kw.

Garden cabin tripping fuse in house

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