What size Armoured cable should I use

Oh right.

Its funny really for a customer I would always use 10mm--never ever had a 16mm indication - its just that 10mm is a nice default in my books.

However I used 2.5mm armoured for my summer house - what the heck its going to have a couple of sockets and a light, and remote controlled actuation for for Victorian style lighting column..there is still plenty of headroom left after plugging in a small heater and stuff..

 

The best advice was given earlier.

Dig the trench and install a duct ready for any size cable.

 

Yup and thats the extent of the project to be undertaken

 

So,after 8 pages of evidence, has the jury reached a verdict on the size of cable the OP requires...

 

6 and 7/8ths

 

I would not mind but the op meant the length.

 

Interesting thread. This isn't a new circuit, it's wondering about an eventual consumer unit upgrade and probable changes to the garage power consumer unit done years ago. That area is in need of some maintenance.

Newer garage CU's usually come with 32amp and 6amp mcb's. So wondered about drop on 6mm with a 38a load. Turns out that at 25m it's slightly over 3% so while the sockets etc are ok the lighting isn't. That would be a 6ft 80w tube so in practice it wouldn't see 38amps. So would the cable need resizing to bring the lighting circuit into spec? The SWA cable as far as ratings go is ok.

When the electrician upgrades the house consumer unit I would inclined to ask him for a separate 100ma rcb on the feed to the garage so that the garage 30ma would rule. That would be a new circuit. Implications anyone?

Dropping the 32amps - need to check but suspect not with a lower power level welder and a compressor running at the same time.

John
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Pity you can’t spell electrician thou

 

Always the way I would go. 2 core and TT it

 

I've heard that some use 3 core and add the amour to the earth circuit to lower the resistance. I've also heard comments from people with more "complicated" diy sheds etc that have a ground spike fitted being told by electricians to **** on it if any problems. Some don't seem to like them.

I'm wondering about them for bonding our gas supply due to how the cable will have to run if it's done that way. Seems the distribution people would quote on the basis of running cable around the front door.

John
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Why would you need to protect the swa with an rcd .dont need it unless it’s tt in the house

 

6 & 7/8 of wattLOL