Ring Fused Spurs and overload protection (433.1.204)

[Pretty Mouth]

Yes, you're completely right. I was looking at Ref Method A. I think I've been at this too long without a break!

I was running it in 2.5mm T&E as it was going to run through a wall and back entry into an outside socket for the garden.

I can't believe I was looking at page 505 earlier too.

Many thanks for your help. Glad I'm getting this right now at the design stage rather than having to go back and change something!

Where did you find the ref meth B for T&E, can't find it the regs or OSG?

P158 of the OSG, or table 4D2A p403 BBB. It's the table for multicore cables.

 

[Steve T89]

See what the other guys think, but i normally fit a dp switch inside to completely isolate, but with a SFCU, they have the option to extend from that one socket to another

I hadn't thought about a DP isolator. Originally they were going to put power out to a small summer house, so would have done, but they changed their minds. (Shame i was looking forward to putting an earth rod in!)
I can put one in if necessary and a switched FCU would be better for future proofing, good idea.
Thanks again!

 

[Steve T89]

P158 of the OSG, or table 4D2A p403 BBB. It's the table for multicore cables

Ahh of course, makes sense now. I had the flat cable blinkers on.

You'd never believe I only got one wrong on my regs exam. Ha!
Cheers again!

 

[brianmoooore]

Cable grouping derating sometimes needs a bit of common sense factored in. An almost unloaded cable, such as a lighting feed with only a couple of lights further on probably takes heat from your loaded power cable, actually increasing its load capacity if anything, rather than decreasing it.

 

[telectrix]

you won'tfind a ref. method B for T/E in conduit as the regs were written assuming that conduit was used only for singles.

 

[LastManOnline]

Cable grouping derating sometimes needs a bit of common sense factored in. An almost unloaded cable, such as a lighting feed with only a couple of lights further on probably takes heat from your loaded power cable, actually increasing its load capacity if anything, rather than decreasing it.

Brian. Glad to see you have had a change of heart about the role "common sense" can play in electrics ?

 

[LastManOnline]

Cable grouping derating sometimes needs a bit of common sense factored in. An almost unloaded cable, such as a lighting feed with only a couple of lights further on probably takes heat from your loaded power cable, actually increasing its load capacity if anything, rather than decreasing it.

I like your comment by the way. And fully agree that there are other factors which can influence decreasing or increasing cable carrying capacity. For instance the Op is talking about installing trunking in his garage rather than indoors in the utility or kitchen. A garage could well be 10 to 15 degrees cooler than indoors which has a direct impact on cable rating.Its like comparing an insulated attic to an uninsulated one.