Consumer units

20150804_090444_zpsnemyqvxv.jpg
 
Sponsored Links
That doesn't look like armoured. Any markings on the cable? I think you need to be thinking about redoing it with the correct cable and at the right depth.
Or confiscate your wife's spade. She can dig over my garden if she's desparate !
 
I also agree that it doesn't look too much like armoured cable, but it's impossible to be sure from the pics. The degree of 'bendability' does not prove anything very much - this is 3-core 2.5mm² SWA (sorry about focus, or lack of it!)....


As has been said, seeing what happens at the ends of the cable is the best way of being sure (plus the fact that SWA usually has raised lettering on the outside).

Kind Regards, John
Edit - where did my photo go? It won't let me re-insert it. I'll try again later!
 
Sponsored Links
The sheath looks more like rubber to me than pvc.

Looks it's taking a lot of force to bend that SWA into that U shape!
 
The sheath looks more like rubber to me than pvc.
It does to me, too - but, as I said, it's impossible to be sure.
Looks it's taking a lot of force to bend that SWA into that U shape!
It may look that way, but it really didn't involve any appreciable force! Mind you, it's again impossible to tell from a photo - that bit of SWA now has a semi-permanent 'U-bend' in it - so I could now take another photo appearing to show me 'bending' it to that shape with my fingertips (maybe even 'through an egg'!!)!!

Kind Regards, John
 
There is no permanent deformation in my cable. It went back to hanging vertically and you wouldn't tell which bit I bent.

As such, pretty sure it is not armoured.

Outside did feel more like rubber than pvc, left black marks on my hand. No lettering that I can see.

Will check the end of the cable when I get chance.
 
Bend a cable too tightly, ( smaller radius than the manufacturer's minimum bend radius ) and you may damage the internal construction that could result in premature failure of the insulation between cores.
 
There is no permanent deformation in my cable. It went back to hanging vertically and you wouldn't tell which bit I bent. .... Outside did feel more like rubber than pvc, left black marks on my hand. No lettering that I can see.
I agree that those facts, taken together, suggest that it's extremely unlikely that it's armoured cable (SWA).

Kind Regards, John
 
On a related note, there is an unused shower supply in the loft - could that be used for the garage?
That's on the house CU RCD.

So even with a garage CU, the angle grinder 1 cable 0 fight you describe could well take that out, leaving you in darkness in the garage and with no power to any sockets in the house.

If you really want a garage CU, then you need the sub-main supplying it to come off the meter tails via a switchfuse, not from the house CU, and you need it to contain RCBOs, and not an RCD main switch.
 
On a related note, there is an unused shower supply in the loft - could that be used for the garage?
That's on the house CU RCD.

So even with a garage CU, the angle grinder 1 cable 0 fight you describe could well take that out, leaving you in darkness in the garage and with no power to any sockets in the house.

If you really want a garage CU, then you need the sub-main supplying it to come off the meter tails via a switchfuse, not from the house CU, and you need it to contain RCBOs, and not an RCD main switch.



Very helpful, thank you (y).
 
So it's now pretty clear that the current cable needs replacement. The question you need to ask yourself is what do you want out of the electrical system in the garage.

At the one end the cheapest option would just be to replace that rubber flex with correctly burried SWA. This would fix the electrical safety problems but would leave the load in the garage limited to 13A total and would also mean that in the event of an electrical problem in the garage (including your grinder through cable scenario but also including more insiduous issues like RCD trips caused by damp) disruption to the house electrics is likely.

Using the shower cable would allow you to have a mucher higher current capacity (useful if you ever want to fit a car lift or use a heater at the same time as a large power tool) than the current setup and would allow you to seperate the RCD protection for the garage from the rest of the house. Unfortunately due to 17th edition requirements on protection of concealed cables the RCD protection would almost certainly have to be located in or near the house CU. That would mean that if it trips you would lose all power in the garage and would have to walk back to the house to reset it.

A new run of SWA all the way back to the house CU location would allow you to chose whatever current capacity you desire (up to the overall limit of your installation) and would allow you to put RCD protection at the garage end and even split it between different items in the garage if you wish. Using a switchfuse connected to the tails rather than a MCB in the non-RCD side of the house CU as BAS suggests would reduce the chances of the house end tripping/blowing before the MCBs in the garage CU since fuses tend to be a bit slower than MCBS at disconnecting short circuits but it means if it does blow you have to replace the fuse which can be substantially more inconvianiant than resetting a MCB.

A rule of thumb is that MCBs are usually faster than fuses at disconnecting short circuits and for devices of the same type a factor of 3 difference in current rating will probablly give discrimination but there is no gaurantee, especially with MCBS where the behaviour of the magnetic trip teds to be fairly binary (it either trips or doesn't). If you see loss of light after an electrical accident as a problem I would recommend installing emergency lighting rather than worrying too much about dsicimination between protective devices.
 

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Sponsored Links
Back
Top