Part of the upstairs electrics not working

[GDPAMG]

Morning,

An upstairs FCU and a number of lights have stopped working but nothing has tripped in the CU downstairs

In the airing cupboard is an immersion heater with hard wired digital timer (working) and a shower pump with an FCU (not working and no light on the FCU)

My bedroom/ensuite lights sockets etc all work ok, but the lighting in the other two bedrooms, bathroom and landing don't work. (Bulbs not blown).

The only clue I have of anything going wrong is that the other night when switching the master bedroom light off, my Mrs noticed that it had caused the light in the 3rd bedroom to go off for a split second before coming back on again.

I tested this last night a couple of times and sure enough, off went the light in the other bedroom. Then the lights in the other rooms went off all together and wouldn't come back on.

I can understand if the fuse has gone in the FCU or the FCU/pump is knackered but don't get how this ties in with the lighting issue.
(They definitely failed at the same time).

Been in the house just over 5 years and there have been no amendments to the electrics and the house itself is about 17yrs old.

Only had very limited time to look at anything under torch light this morning before leaving for work, but would appreciate any pointers in the right direction for when I get home.

 

[PrenticeBoyofDerry]

Firstly Investigate at the light in the third bedroom, it could be that you have a loose looped in live or neutral. It is normal for the loops to be found at the light fitting, but not unheard of for loops to be made at switches. (but don't rule out concealed joints either).
It could be possible for a loose live/neutral conductor, at a fitting/switch at a light further up the circuit also causing this problem.
Safely isolate circuit prior to removing any covers from fittings/switches, then prove the circuit is dead prior to touching anything.
Take a note of where the conductors are before pulling at any of them, just in case they need to go back in the same spot.

 

[GDPAMG]

Thanks for the response, I was guessing at a connection issue somewhere along the line, just confused as to how the lights and the FCU for the shower pump both seem to have been affected at the same time.

I will check the connections and see if anything looks to be amiss.

The cable which runs to the FCU disappears off in to the loft which leads me to believe it may run in to a junction box somewhere as I'm sure the other cables to sockets run directly from upstairs to down.

 

[securespark]

Have you replaced the fuse in the FCU?

It is not unknown that FCU's have been tapped off the LOAD side for additional stuff, rather than the FEED side.

 

[maltaron]

As the problem seems to ensue from the operation of the main bedroom switch it is almost certain that there is a loop in wire at that switch, which initially was loose and has now fell out. Unless there is some dodgy wiring with a shower pump on the lighting circuit, I would think that the shower pump problem has occurred at about the same time as the lighting. As you seem to have two possible problems with possibly loose connections, and the wiring has not been looked at for 17 years, I would consider that it is past time for an EICR.

 

[GDPAMG]

So I checked the master bedroom switch which is a 2 gang 2 way as there are 2 ceiling pendant lights and found this which looks horrific but I'm no expert:

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• GDPAMG
• 24 Oct 2013
• 1

The wire which loops from one side to the other didn't even have a screw in it on one side but the lights still worked.

Wires along the top A 1 way is connected along with B COM

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• GDPAMG
• 24 Oct 2013
• 1

Wires along the bottom - A COM and B 1 way:

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• GDPAMG
• 24 Oct 2013
• 1

The loop connects A 1way to B one way.

What the spare wire is doing I have no idea and the earth is not connected to anything.

3rd Bedroom:

This has a single dimmer to the ceiling light:

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• GDPAMG
• 24 Oct 2013
• 1

All connections are sound.


The FCU - I will replace the fuse and check. It does run in to a junction box in the loft which also has the bathroom extractor running in to it.

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• GDPAMG
• 24 Oct 2013
• 1

That's as far as I've gotten so far...

 

[PrenticeBoyofDerry]

The first picture shows a live cable that is not terminated, that would be the first thing I would be looking at correcting, it is very much possible that this is the reasoning behind your power loss.

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• GDPAMG
• 24 Oct 2013
• 1

I would be thinking that if you terminated this in to one of the switch terminals that has the link across it (I think the switch terminal that shows the link on it's own, showing the copper conductor, could be used, make sure both cables are terminated fully with no copper showing, but not trapping any of the PVC insulation within the terminal) you should hopefully be getting power back to the lights then.
Do you have a means of safely testing for voltage?
I also suspect that there will be a number of CPC/earths within the green&yellow sleeve (possible 3), these should ideally be individually sleeved and terminated together in a connection block, not twisted together in a single sleeve.

 

[GDPAMG]

Thanks again for the reply - All sorted!

I terminated the 'spare live' as indicated and hey presto, everything came back to life including the FCU.

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• GDPAMG
• 24 Oct 2013
• 1

So it looks like those two wires had just been looped and pressed in together without a screw for 17 years before finally working their way loose!

You were right about the 3 earth's in one sleeve, I've now separated these out and terminated into a small block.

Should I be concerned that the FCU seems to tie in to this lighting circuit?

 

[securespark]

Is it a shower pump?

They're best not put on the lighting circuit.

As for the switch...did you manage to pinch a screw from another unused terminal to secure those conductors?

 

[PrenticeBoyofDerry]

TBH I cannot see any issues with connecting a low output shower pump to a lighting circuit, providing the lighting load plus pump output have been calculated to be suitable.

 

[GDPAMG]

Yes it's a shower pump and has never given me any trouble. Only info I can find about it on the net states:

'Pump requires 230volt AC supply fused at 3amps via a double pole isolator with contact gap of at least 3mm'.

It's a Bristan Varispeed 50 - http://www.bristan.com/WebRoot/BristanNewDB/Shops/Bristan/Products/WEB_DATA-1055884-1-D6-1.PDF

I know it's is a 3A fuse in the FCU as I replaced it as part of diagnosing the problem.


Yep, I used a screw from one of the unused terminals.

 

[PrenticeBoyofDerry]

The pump has 245W impeller, so only requires 2A. But the MI does state 30mA RCD protection, so if you do not have this lighting circuit protected by 30mA RCD or the FCU is not integrated with this protection, I suggest that you replace existing FCU for one that combines both 30mA and down-fusing.

 

[GDPAMG]

Ok, thanks again for all your responses