Any electricians in the house?

[Lonsdale73]

Anyone able to offer any advice please?

I use my garage for a workshop and it had an electrical supply already installed when I moved in. The box marked 'M' in a red circle is the mains switch which runs back to a fuse box in my kitchen. There are three lines out of it, one powering the sockets dotted around the garage, a second runs to my studio, powering the sockets in there and the third (marked FM in the blue circle) runs to the unfused switch on the left of the photo. A spur from this (marked ESL in the green circle) to the fused switch goes to a exterior PIR that I'd forgotten was even there. The other line (IL in the yellow oval) used to run to an old strip light which flickered so bad it was like a disco strobe. I took that out some years ago and converted the cable to terminate in a standard 3 pin socket into which I plugged a site lamp. That worked fine till earlier this year when I managed to trap the site lamp's cable which blew the bulb and tripped out the circuit breaker in the kitchen. I replaced the lamp, reset the CB and power was resumed - except in the lamp. I checked the bulb was properly seated and tried several others but it still didn't light up. Plugged the lamp into one of the other sockets and it worked fine. Tried something else in the IL socket and nothing.

I was puzzled as to why a blown lamp would cause a socket to stop working. I have since removed the socket, connected it to a length of flex with a 13a plug to make a short extension lead and that works fine. I've tried other sockets - including a brand new one purchased today - and still nothing. Could it be a fault within the left hand switch?

 

[Dibs-h]

get yourself one of these, if you don't have one - https://www.screwfix.com/p/lap-ms8907-v ... -pen/3222g

Check the cable going into the left switch. Should be live (tester will squeak). Then check cable IL with the switch off - shouldn't squeak. Then check again with the switch on - would expect it to squeak. If you wired a socket (correctly) to the end of that, and check (touch) the (new) socket with the tester, I would expect it to squeak.

From what you've written - I would expect power at the socket\cable, as you swapped the socket out for an extension and it works. You've tried something else in the socket and it doesn't work either.

Have you swapped the IL cable out of the switch for another cable - say proper 2.5mm T&E?

I'm wondering if the IL cable has some kind if internal fault\issue from when you trapped the lamp cable and things went weird.

HIH

Dibs

 

[Lonsdale73]

I'm wondering if the IL cable has some kind if internal fault\issue from when you trapped the lamp cable and things went weird.

HIH

Dibs

Thanks for that.

I'd wondered that, not through any real knowledge but by process of elimination however didn't know if it was possible. I was about to run that cable straight to the new socket but light was fading by that time so I'll try that in the morning and if it still doesn't work I'll try a replacing the cable.

I have one of these http://www.philex.com/products/product/philex-cat-iii-10a600v-digital-multimeter/

 

[Dibs-h]

Sorry - just re-read your post again.

You took the socket that was on IL, wired to it a length of flex & 13a plug and tested it on a socket somewhere & it works. I missed this bit first time round.

Change out the cable IL & you'll be sorted I reckon. As a test - why not get that extension lead you made up with the former IL socket, take off the plug and wire it in place of IL and see how you get on?

Dibs

 

[nev]

at a glance at the picture it looks as though the fused spur and light switch are connected to each other, so either the spur feeds the light switch (likely) or vice versa (unlikely). If the former have you checked the fuse in the spur?

 

[Lonsdale73]

at a glance at the picture it looks as though the fused spur and light switch are connected to each other, so either the spur feeds the light switch (likely) or vice versa (unlikely). If the former have you checked the fuse in the spur?

The fused spur supplies an external PIR lamp and checking the fuse was the first thing I did.

The previous owner was ex-military who got into home security in a big way. There are FIVE PIR lamps in total - one covering the front of the garage which I can sort of understand as they'd light up when trying to park in the dark. another the front door which is backed-up by a separate light operated manually from the inside, one over the kitchen door, one over he patio and this one whose function isn't clear to me although thinking back to the trailer that was left behind he might have kept a boat in that area.

There are motion sensors everywhere which flash and blink all the time even though I've no idea what they are connected to and the master bedroom contained a small box about the size of a packet of Tic-Tacs with a key in it. Turned out to be a panic button which triggered an ear piercing alarm which I had no idea as to how to reset since someone at some point had changed the stop code!

 

[Eric The Viking]

Commonly (but not every time) when a filament bulb blows, the tungsten becomes vapourised at the last split second, and a plasma forms across the break. This is a very good conductor, and there is a current surge at that moment. This will either trip any MCB or blow any fuse in that circuit.

So I would guess that somewhere there is another fuse in the circuit. Either that or, as others have suggested, the thin cable (IL) is damaged, or has come loose in the silver metal-boxed switch. That switch, incidentally, looks as if it might be double pole - switching both live and neutral - but the switch next to it, with the fuse, probably only switches the live side. It is clumsy, but that might be a reason for having both of them, so that you can isolate the complete circuit with the silver switch.

It is also possible, but quite unorthodox and unlikely (and naughty), that there is some sort of fuseholder inside the silver box.

And finally, some mains extension sockets, typically multi-socket outlets and plug-in, 3-way adaptors, have built-in 13A fuseholders. With 13A extensions you often end up with a string of (unnecessary and unwanted) fuses all in the same circuit, so it's pot luck which one actually goes (or several).

I'd check I hadn't missed one.

 

[RogerS]

Don't forget to check for a loose neutral.

 

[deema]

My recollections of the wiring regulations are a little fuzzy these days it’s been a long number of years since I was familiar with them.

I believe that the setup you have is not very good. I don’t believe it complies with the wiring regulations when it was installed / updated and does not comply with the latest requirements. The best solution would be to replace the master switch with a consumer unit that will separate out the lighting and ring mains circuits. The added advantage will also be that by having a distribution board with modern circuit breakers and earth leakage detection you will be a lot safer reduce the present risk (IMO) of a fire / electrocution caused by a fault.

The cost of a consumer unit (garage unit would I believe suffice) is minimal and it will also stop you having problems selling your house in the future.

 

[Lonsdale73]

My recollections of the wiring regulations are a little fuzzy these days it’s been a long number of years since I was familiar with them.

I believe that the setup you have is not very good. I don’t believe it complies with the wiring regulations when it was installed / updated and does not comply with the latest requirements. The best solution would be to replace the master switch with a consumer unit that will separate out the lighting and ring mains circuits. The added advantage will also be that by having a distribution board with modern circuit breakers and earth leakage detection you will be a lot safer reduce the present risk (IMO) of a fire / electrocution caused by a fault.

The cost of a consumer unit (garage unit would I believe suffice) is minimal and it will also stop you having problems selling your house in the future.

Excuse my ignorance here but isn't that what the unit on the right labelled M is?

Following suggestions I stripped out the cable IL and replaced it with a length of 2-core 6 Earth. That didn't work so I tried bypassing the switch(es) and wired cable FM straight to the 2-gang. That didn't work either so figuring if IL could have a fault then so too could FM so next stop was to strip that out which meant opening M. This wasn't easy and I have a vague recollection of getting to this point when it first happened and deciding it would be simpler - and possibly safer - just to plug the lamps into the socket on the opposite wall. Determined this time I did manage to free the closure and get in to the box marked 'M' where it has two Wylex 15a fuses, one going to the lights, the other to the sockets. And I think that's the fault, the fuse for the light circuit has blown. So I've wired everything back as it was and ordered some fuses, see what that does when hey arrive.

 

[Eric The Viking]

I rest my case m'lud...

Seriously, that MEM breaker box is of an age when it might have had wired fuses - have you fusewire, in which case lighting would be 5A (or 6A) typically, but remember not to plug something else into the 13A adaptor you made up!

As discussed elsewhere, those fuses protect you and the cable (you to a _lesser_ extent). The world won't end with the wrong value fuse in circuit, but it's not as safe as it might be. You can't swap fuseholders of different sizes, but you can use bigger fuse wire for a very short time, enough to test if the fault clears. If they are cartridge-type fuses, none of this applies as thy usually can't be swapped over.

 

[Lonsdale73]

I rest my case m'lud...

Seriously, that MEM breaker box is of an age when it might have had wired fuses - have you fusewire, in which case lighting would be 5A (or 6A) typically, but remember not to plug something else into the 13A adaptor you made up!

As discussed elsewhere, those fuses protect you and the cable (you to a _lesser_ extent). The world won't end with the wrong value fuse in circuit, but it's not as safe as it might be. You can't swap fuseholders of different sizes, but you can use bigger fuse wire for a very short time, enough to test if the fault clears. If they are cartridge-type fuses, none of this applies as thy usually can't be swapped over.

It has these: https://www.screwfix.com/p/wylex-sfcfl15-15a-cartridge-fuse/59949#_=p

 

[deema]

From what you’ve said, and what I can see either the person who instalked the setup was completely incompetent, or it’s been DIYed afterwards to a state of being dangerous. Seriously, this is not an area where inexperience and tinkering is not a good idea, get a proper electrician to sort it out properly. You need a new consumer unit and the wiring putting right.

 

[Lonsdale73]

Fuse replaced, all working again. Despite having the cover off just the other day, the beggar didn't want to move again today!