Strange little situation... any thoughts?

[Gigagator]

Firstly, my fuse box has 6 fuses (see picture). There's a fuse for circuits as follows and in order from left to right; shower, d/stairs lighting, u/stairs lighting, water heater, plug sockets, cooker.

Untitled

• Gigagator
• 6 Feb 2012
• 1

I was replacing a couple light switches around the house today and decided to pull all the fuses except the fuse for the sockets as I wanted to keep some stuff running.

But I noticed that as well as the plug sockets, the combi boiler was on too, which I would have thought would run on a different circuit to the sockets.

I would have assumed it would run through the 'Water Heater' fuse at the fusebox as we had the combi boiler installed in place of the old water heater etc in 1997.

Out of curiosity, I went and pulled the fuse for the plugs out and instead put in the fuse for the 'water heater'. When I did this, all the plug sockets and the combi came on.

Is it dangerous to have the boiler on the same circuit (seemingly) as all the sockets, and how would two separate fuses control the exact same circuits?

 

[mikhailfaradayski]

It seems possible that the (assumed) ring circuit supplying the sockets and boiler has each end fitted to a different fuse.

This really needs rectifying pronto as the next person who makes assumptions that the place is wired correctly might have a very nasty shock

 

[plugwash]

There is nothing wrong with having a combi boiler supplied from the socket circuit.

However you do have a sersious problem that needs too be fixed Some numpty has cross linked the circuits. This needs to be fixed as it means the circuit will not have proper overcurrent protection. To fix it you need to map out the wiring so you can work out which link to remove to break the cross-linking AND leave the two circuits in a compliant state. From the way you ask this question I suspect doing so is beyond your skills.

As a temporary measure I would suggest reducing the fusewire in the sockets fuseholder to 15A, this should make the installation reasonablly safe until it can be sorted out properly.

 

[SUNRAY]

Firstly, my fuse box has 6 fuses (see picture). There's a fuse for circuits as follows and in order from left to right; shower, d/stairs lighting, u/stairs lighting, water heater, plug sockets, cooker.

Untitled

• Gigagator
• 6 Feb 2012
• 1

I was replacing a couple light switches around the house today and decided to pull all the fuses except the fuse for the sockets as I wanted to keep some stuff running.

But I noticed that as well as the plug sockets, the combi boiler was on too, which I would have thought would run on a different circuit to the sockets.

I would have assumed it would run through the 'Water Heater' fuse at the fusebox as we had the combi boiler installed in place of the old water heater etc in 1997.

Out of curiosity, I went and pulled the fuse for the plugs out and instead put in the fuse for the 'water heater'. When I did this, all the plug sockets and the combi came on.

Is it dangerous to have the boiler on the same circuit (seemingly) as all the sockets, and how would two separate fuses control the exact same circuits?

This needs sorting quickly for sverl reasons, my first guess is it may be incorrect or faulty wiring in the boiler system.

Its not unsafe to have the boiler on the ring circuit, assuming its wired and protected correctly.

 

[Gigagator]

To 'SUNRAY', by 'protected correctly', do you mean by an FCU as it has this, with a 3A fuse.

Here are a couple more pictures inside the fuse box. Don't worry it was all isolated, apart from the live tails coming in of course, I can't isolate those regrettably.

Untitled

• Gigagator
• 6 Feb 2012
• 1

Untitled

• Gigagator
• 6 Feb 2012
• 1

Looking at the two fuses in question, does this tell you anything about how it may all be wired up?

Three wires going into the 'Plugs' fuse and one wire into the 'Water Heater' fuse. As an untrained person, this baffles me.

 

[mikhailfaradayski]

Can't really say just from looking where the error is. It may be as Plugwash says, theres a link bridging the circuits somewhere in the house. It could also be that what you have is the two ends of a ring split over two fuses.

It will probably need a certain amount of disconnecting and testing continuity here and there with a suitable meter.

If you don't feel comfortable doing this (or you on't have any test equipment), then it may be time to bite the bullet and call a sparky in before someone has a nasty accident.

 

[riveralt]

There is no obvious link between the 15Amp fuse and the 30Amp fuse at the Consumer Unit. Assuming the 30Amp has a ring final circuit and a spur and the 15Amp is a single radial final circuit.
But your description of what happens when you energise the two circuits separately suggests to me that you have a bridge on the ring final circuit - possibly between the combi boiler and the water heater.
Whatever is the problem is does need sorting out asap.

 

[SUNRAY]

To 'SUNRAY', by 'protected correctly', do you mean by an FCU as it has this, with a 3A fuse.

Here are a couple more pictures inside the fuse box. Don't worry it was all isolated, apart from the live tails coming in of course, I can't isolate those regrettably.

Untitled

• Gigagator
• 6 Feb 2012
• 1

Untitled

• Gigagator
• 6 Feb 2012
• 1

Looking at the two fuses in question, does this tell you anything about how it may all be wired up?

Three wires going into the 'Plugs' fuse and one wire into the 'Water Heater' fuse. As an untrained person, this baffles me.

That all looks quite normal and fairly neat compared to many I have seen.

I doubt if the fault is in the fuse box so that needs to be closed up.

It could also benefit with some updating but you have a moore pressing situation to sort out and to be blatantly blunt Is time to call in an expert unless you think you have the ability to identify every cable in your power circuits

As an untrained person, this baffles me.

 

[riveralt]

On second thoughts it is possible that person who fitted the combi in 1997 has put that live conductor in the 30Amp by mistake instead of the 15Amp. Then proceeded to wire the combi fcu to the water heater circuit.
But again - without proper testing just stab in the dark.

 

[plugwash]

Here are a couple more pictures inside the fuse box.

They don't really show anything that couldn't bee seen in the first picture. The immersion fuse has one wire as would be expected. The sockets fuse shows three wires which is a little unusual but not nessacerally wrong (it's acceptable to take a spur from the origin of a ring or radial circuit).

As I already said someone needs to map out what wiring goes where so that they can work out what changes are needed to safely seperate the circuits.

 

[PrenticeBoyofDerry]

You either have a bridge between circuits or your RFC is being supplied by two fuses.

The only way to find out for sure is by having the circuits tested.
You could try removing each conductor at a time from the fuse protecting the RFC. See what powers off!
Some one could have been altering circuits and parked the old immersion circuit in the RFC fuse and the other leg of RFC in immersion fuse.
But I would recommend having it tested for continuity/r1+r2

 

[Gigagator]

To answer all, I'm not in a position to carry out the work myself, I don't know enough and aren't properly equipped aside from a multimeter. One day hopefully I will be as I'm interested in pursuing a career in electricals.

Is this an immediate risk to myself and the family?

I didn't even know about it until today and we've never had any problems with the electrics, never even so much as a fuse blowing.

The reason I ask is that a new kitchen is planned in early 2013 and we plan on having all the electrics gutted and redone then. So if it is something that can wait until then, then that works out great.

I've found a few bizarre things today though. For instance, I was changing the double light switch in the kitchen and found a wire tucked away at the back of the box that had been cut and had bare ends! I couldn't test with the multimeter as there's no neutral present at the switch but I taped it up firmly for now.

It would appear the cut off wire was one of the original lighting wires for one of the two kitchen lights. Another T&E has been added as you can see, practically on the surface of the wall and coming in at an odd angle.

Untitled

• Gigagator
• 6 Feb 2012
• 1

But then what's this in the bottom right of the box? Why it's a bit of 2-core lawnmower flex. Luckily I discovered that had been cut off both ends, it leads into a pantry area. I reckon someone had tried to use it for a light, not realising they needed a neutral too.

 

[mikhailfaradayski]

Just had a second look at the pictures and now think you really should be calling a spark in sooner rather than later.

Whilst hes there, ask him to check out your earthing and bonding is adequate aswell.

 

[mikhailfaradayski]

The new switches you were fitting, what type are they?

 

[Gigagator]

The new switches you were fitting, what type are they?

They're plastic. I'm aware that none of my light circuits seem to have an earth and therefore I've ensured all light fittings etc are all plastic.

Strangely, looking inside the CU, the downstairs lighting circuit is earthed but the cable for the upstairs lighting circuit uses only two core cable with no earth.

Nonetheless, various cables on the downstairs lighting circuit don't have an earth at all (not even snipped off, they just don't have one) so it doesn't seem to matter what's going on in the CU anyway.

By the way, I found a lot of the screw terminals in the CU were quite loose and so I tightened everything, was I right to do this?