Lighting off 30 amp cabling

[caveman2]

I want to run an outside light using the 30 amp power cable in the garage.
Can I take a spur off a power point to a 5 amp fused spur and the use 1mm T&E for the switch and light.
The cabling for the light will be directly on the wall behind the power cabling in the garage with no viible cables showing.
the only point I am unsure of is if it is safe practice to use an FSU unswitched with 2.5mm cable from power point and then 1mm to supply light and switch.
Is this OK

 

[PrenticeBoyofDerry]

That sounds okay to me. I assume the circuit is a ring final circuit, if so the fused spur should not really be taken from an outlet that is already a spur.
Does the circuit your taking the feed from have RCD protection?

 

[caveman2]

I am afraid not. The consumer unit is in the garage and the power canle to a double socket outlet is a spur from one of the rings into the house. Cable intercepted with a block connector before the cable entered the house. Also the fuses are all the wired types - original CU with the 25 year old house.

 

[ban-all-sheds]

You are not allowed to have a consumer unit supplied by a spur from a ring final.

Whoever did that was an ignorant buffoon, and ignorant buffoonery + electrics = danger, potentially lethal.

You need to get an electrician to come and sort out the mess, check for any other outbreaks of idiocy, and do the light at the same time.

 

[PrenticeBoyofDerry]

Is it possible for the socket to be rearranged, so it is not a spur. ie extend the ring final circuit.
Is this socket surface mounted and the cables clipped or run in trunking, rather than buried in plaster?
Do you have lighting circuit in the garage, for a possible feed?

 

[PrenticeBoyofDerry]

I think the OP is saying the CU/Fuse box for the house, is in the garage not a CU is spurred of the RFC.

 

[sparkticus]

There is no way that will meet wiring regulations. The requirement for an RCD is mandatory unless you can run the new circuit wiring in armoured cable or earthed metal conduit. Or keep all the new wiring at least 50mm deep in walls. Otherwise you will need an RCD in that circuit.

More generally, you should consider looking at a consumer unit upgrade to include at least two RCDs.

 

[PrenticeBoyofDerry]

What if the cable is surface mounted?

 

[sparkticus]

Wait, the house CU is in the garage????? no surely not?

 

[sparkticus]

What if the cable is surface mounted?

True but it sounds like it would not all be surface mounted. Assuming the cable needs to terminate through the garage wall.

 

[sparkticus]

Wait, the house CU is in the garage????? no surely not?

No forget my concern. I had it in my mind that the garage was remote. It probably is joined to the house. I jumped to a probable false conclusion.

 

[PrenticeBoyofDerry]

What if the cable is surface mounted?

True but it sounds like it would not all be surface mounted. Assuming the cable needs to terminate through the garage wall.

If the cable is surface mounted in the garage there could be away around this by the means of RCD protected FCU for the light.

 

[sparkticus]

What if the cable is surface mounted?

True but it sounds like it would not all be surface mounted. Assuming the cable needs to terminate through the garage wall.

If the cable is surface mounted in the garage there could be away around this by the means of RCD protected FCU for the light.

You may be right there. You are saying just RCD protect the new circuit from the FCU onwards. I don't like it because it is adding a new circuit to a non-compliant system but I suppose that might obey the spirit of the 17th edition

 

[caveman2]

Thanks for all the input.

"You may be right there. You are saying just RCD protect the new circuit from the FCU onwards. I don't like it because it is adding a new circuit to a non-compliant system but I suppose that might obey the spirit of the 17th edition "

Can you please tell me how I can acheive this

 

[sparkticus]

Thanks for all the input.

"You may be right there. You are saying just RCD protect the new circuit from the FCU onwards. I don't like it because it is adding a new circuit to a non-compliant system but I suppose that might obey the spirit of the 17th edition "

Can you please tell me how I can acheive this

You could use this as the FCU.

http://www.tlc-direct.co.uk/Products/BRH92.html

But and its a big but, you will be extending the circuit of a non-compliant installation. That is, your existing electrical installation does not meet latest wiring regulations. I would personally not do it in a professional capacity but I don't do a lot of domestic electrical work so I will defer final word to others on the forum. I feel sure they will comment soon.

PS, How non-compliant is not known but the fact that you have wired fuses is a clue that it may have problems lurking due to age and may have been poorly DIYed over the years.