Upgrading my garage supply.

[kenny7askew]

answer to the above, in red. the steel wire armouring of the SWA MUST be earthed, even if not used as a protective conductor for the cable, the supply end must be earthed, generally by use of a SWA gland and banjo or earth nut. you can pull the builder upon that.

Thank you you are quite right i should have said MUST not SHOULD

 

[Mr_Freeze]

answer to the above, in red. the steel wire armouring of the SWA MUST be earthed, even if not used as a protective conductor for the cable, the supply end must be earthed, generally by use of a SWA gland and banjo or earth nut. you can pull the builder upon that.

Thanks Tele.
So what about DP isolation at the spur, I know its a nice to have to totally isolate outside, but is it a must that they should've supplied this or not?

 

[Mr_Freeze]

Hi,with double pole spur you will be able to isolate garage in the event of a neutral earth fault in garage to stop house RCD tripping,with more than one RCD on the circuit it will be pot luck wich one trips first if not both,changing to mcbs wont make much difference to discrimination,swa should be earthed

Why not, surely a lighting fault will trip a 6a MCB before a 13amp fuse?

 

[Wilko]

Why not, surely a lighting fault will trip a 6a MCB before a 13amp fuse?

Hi - descrimination between protective devices is an interesting topic. For a short circuit fault where you will have say 500A current, it would be a bit of a race but quite likely the 6A MCB will trip and the 13A fuse will also melt. For an overload fault where lighting was drawing say 18A then the 6A MCB should trip only.

 

[Spoon]

Existing installation has a 5A fuse for the lights and a 13A fuse for the sockets... I don't see the problem.
I have also asked the OP why we are discussing this in private messages and also on the post...

 

[Mr_Freeze]

My apologies I don't use this forum very often and I think ive hit "quote in conversation" rather than reply.
My mistake sorry.
I just wanted to tidy up the install and provide separate circuits to wire from in the garage rather than the all on the 13amp spur in the house.
It would just seem wrong to me to be wiring the sockets from the incoming side and lights from the load side of the fused spur in the garage.
Forget costs and time, I have these at my disposal.
Other than having 2 x RCD's in series (I understand both or either could trip) am I not improving the install by providing MCB protection in the garage.
I am electrically trained a long time ago on industrial kit and have never done domestic regs, so I was searching to find out if:-
a. The builder should've earthed the armoured at one or both ends?
b. Should he have provided DP isolation on the outgoing external supply?

The install doesn't easily allow for replacement of the armoured with 2.5 or to take straight to the house CU.
I'm trying to make the best of a poor job.

 

[Toneyz]

Why not, its my garage?

Mr Freeze... With the greatest respect unless you plan a new dedicated feed from your fuse box, you are wasting time and money....

Apart from the usual circuit design constraints, I can't see why not it is all from a fused spur limiting to 13A can have as many sockets as he likes for convenience.

 

[Toneyz]

Mr Freeze, what do you intend to use the garage for and the load requirements?

 

[Pete999]

Mr Freeze, what do you intend to use the garage for and the load requirements?

Couple of big FREEZERS maybe?

 

[Toneyz]

Couple of big FREEZERS maybe?

Then we are going outside the realms of standard use of a family garage is used for, Oh I get it now

 

[Octopus]

Please don't state the obvious, not helpful.

Actually his input was constructive if you ask me, and as yet you've ignored my earlier response.

As for new builds, they are typically built with many issues .... Trying to get a builder to resolve is almost impossible.

 

[Pete999]

Then we are going outside the realms of standard use of a family garage is used for, Oh I get it now

Doh wake up Ant

 

[Spoon]

Mr Freeze, what do you intend to use the garage for and the load requirements?

I tried asking this... and got this back.

 

[Pete999]

I tried asking this... and got this back.
View attachment 39821

Makes me wonder what I'm going to get back with my comical post? #24

 

[Toneyz]

Makes me wonder what I'm going to get back with my comical post? #24

You are making me think he is an ice cream seller Mr Wippy