Consumer Unit Relocation

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Soldato
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19 Jan 2006
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This may be an impossible question to answer without seeing behind the box/in the wall, but are consumer units normally wired with a fair amount of slack in the cables feeding them?

I want to extend out my bathroom, but to do this I'd need to move the consumer unit roughly 1 metre over from where it's currently located, so that it sits outside the extended part of the bathroom - is the current cabling likely to accommodate this or is it a bigger job than "just move it over"?

I'd be getting a professional in to do it, but I'm weighing up whether while I'm refitting the bathroom it'd be worthwhile to also extend it.
 
Does the mains come into an external electrical box with the meter then into the fuse board?

It most probably be doable but they may need to put a junction box in the ceiling to extend some of the house wiring.
 
Doubtful that there would be 1m of slack to be honest.

Its doable but theres 2 ways it could be done, one would be simply cutting all of the cables and extending the cables to the new location and joining them. The problem with this is, I believe, the junctions/joints need to be accessible so you would have to have a panel or similar to where the joints are, unless its a maintanance free junction box.

The other way would be rerouting cables with the correct length, which is obviously a lot more work.
 
roboamigo said:
The problem with this is, I believe, the junctions/joints need to be accessible so you would have to have a panel or similar to where the joints are, unless its a maintanance free junction box.
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So what makes a junction box maintenance free?

What maintenance would be needed for something like this...

https://www.toolstation.com/60a-jun...yDs4glqkcFNxGkl2ayrO7f3zENrittYRoCW3sQAvD_BwE

Only asking as the concept is a new one to me and I buried similar to the above in a stud wall not too long ago...
 
Screw terminals can come loose and need to be accessible for maintenance, that's in the rules.

If you're hiding junction boxes in the structure then you aren't someone who should be playing with the wiring in the first place. If you didn't know about that what else don't you know about?

This is why we got stuck with Part P.
 
bremen1874 said:
Screw terminals can come loose and need to be accessible for maintenance, that's in the rules.

If you're hiding junction boxes in the structure then you aren't someone who should be playing with the wiring in the first place. If you didn't know about that what else don't you know about?

This is why we got stuck with Part P.
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So in theory screw terminals can come loose. But does anyone actually ever check all of their sockets or junction boxes in the loft? It feels like a low risk situation to me. Or am I wrong? I guess the only loosening mechanism is heating and cooling of the screws.

I know where it is behind the plasterboard, so I could fairly quickly access it. But I don't see it is a likely situation.

Thoughts?
 
TheFew said:
I know where it is behind the plasterboard, so I could fairly quickly access it. But I don't see it is a likely situation.
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What about the next person who buys the place and doesn’t know about your bodges and none compliant modifications? Are you for example aware of the rules regarding where hidden cables are permitted to be installed?
 
bremen1874 said:
What about the next person who buys the place and doesn’t know about your bodges and none compliant modifications? Are you for example aware of the rules regarding where hidden cables are permitted to be installed?
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Yes aware of the theory! Just had not come up against the maintenance free junction box aspect before.

Presumably as the circuit (a shower) is on its own RCD at the CU it is relatively safe if the screw should ever come lose. The junction box itself is fixed in place, as it the cable. So it can only really be a theoretical heating contraction and expansion of the screw that could lose the connection surley!
 
I would have thought that a high current circuit like that is probably the worst place to possibly (even if it's unlikely) have a loose connection hidden away beyond reach. If that starts arcing and/or heating it isn't going to be pretty.
 
bremen1874 said:
I would have thought that a high current circuit like that is probably the worst place to possibly (even if it's unlikely) have a loose connection hidden away beyond reach. If that starts arcing and/or heating it isn't going to be pretty.
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I don't disagree! But apart from ready access I guess it is no different to the wiring that clutters a lot of lofts?
 
TheFew said:
I don't disagree! But apart from ready access I guess it is no different to the wiring that clutters a lot of lofts?
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Its against the regulations. If this installation caused a fire then you will be on iffy ground with your home insurance as well.
 
200sols said:
Its against the regulations. If this installation caused a fire then you will be on iffy ground with your home insurance as well.
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Agreed. Good point. So i guess I need to understand the risk versus the likelihood for an occasional use item like the shower.
 
TheFew said:
Agreed. Good point. So i guess I need to understand the risk versus the likelihood for an occasional use item like the shower.
Click to expand...

I think you’re missing the point.
You do not want a loose connection arcing away generating heat, you definitely do not want that buried in a wooden stud wall surrounded by flammable insulation with no chance of being able to dissipate that heat buildup. If the junction box itself didn’t catch fire the heat build up would ignite something else surrounding it. This is obviously made worse with a high current circuit such as the shower. The amount of times it’s used doesn’t make a difference.

You can try and compare this to cables in a loft all you want but here’s a few reasons;

As the junction box and cabling would not be buried there is less chance of heat build up.

When you have a electrical condition report carried out the person doing this will easily see these junction boxes in the loft to check - they will not be able to see the ones that have been buried out of sight.
A junction box in the loft I would expect, one in a stud wall - definitely not.

Its also just good working practice. Eliminate the use of junction boxes all together. If not then the next best thing is a maintenance free one, hardly any more expensive and they are just safer - no argument on how screws may come loose or how likely it would be, you’ll be surprised what heat cycling will do.
I also trust you can ensure you’ve tightened up all those connections tight enough and that there has been absolutely no movement on anything that may put strain on the terminations during the installation or construction of the stud wall. You just don’t get that uncertainty with maintenance free boxes providing they have been installed/used correctly.
 
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Do you get maintenance-free junction boxes for 6mm/10mm cable? Never had reason to look, but a quick Google doesn't show anything obvious.

For cable of that size, wouldn't you require crimped joints if you want them inaccessible? Not something you're going to be doing without the correct tools.
 
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