SWA termination

Help Support Talk Electrician Forum:

davetheglitz

Electrician
Joined
Mar 18, 2008
Messages
822
Reaction score
1
Location
Saltash, Cornwall
More basic advice please - need to check if my gut feelings are right!

SWA from house to garage. 3 core SWA at house board, 2 core at garage. Presume there is a joint somewhere. Plan to re-use a plastic 2 way RCD CU in the garage.

I have been told to dress the cable so that a few cores of the SWA will reach the earth bar in the CU (sleeved of course) and trim and insulate the others off. I don't think this is right as I can't rely on the earth being continuous - not knowing how the joint was made.

I'd have thought that either

a) a terminal box with a gland and banjo should be used or

B) all of the sheathes should be connected together (could group in three braids) and either put directly onto the earth bar.

Am I being pedantic or is my gut feel right?

Would the split off a few SWA method be acceptable if there was no join in the cable?

Thanks

Dave

 

Theorysparky

Domestic Electrician
Joined
Feb 18, 2008
Messages
4,233
Reaction score
0
Dave

Firstly is there any chance you can use an adaptable box to terminate the swa outside the house and use appropriate t+e to the board.It would be a much better job

3 core down to 2 :( i would do continuity checks to find out whats been joined and mark them up.

would be ideal to find the joint of course

 

davetheglitz

Electrician
Joined
Mar 18, 2008
Messages
822
Reaction score
1
Location
Saltash, Cornwall
Hi TP - I appreciate your point regarding the adaptable box - but unfortunately it is not my job - I was just drafted in to help out - so I'm restricted in what I can do.

I like the idea of a continuity check - but cant se how it would work. If the SWA sheathes were touching you would get continuity - so couldn't readily differentiate the connected and touching strands - that's why I suggested connecting all of them at the garage CU.

Cheers

Dave

 

Theorysparky

Domestic Electrician
Joined
Feb 18, 2008
Messages
4,233
Reaction score
0
So then you either have a redundant core at the cu or the sheath has been jointed to it at the joint (where ever that is)

is that right

 

Theorysparky

Domestic Electrician
Joined
Feb 18, 2008
Messages
4,233
Reaction score
0
just re read yr post are u finishing off someone elses work ???

 

davetheglitz

Electrician
Joined
Mar 18, 2008
Messages
822
Reaction score
1
Location
Saltash, Cornwall
Hi TS - yes I was attemping to finish off someone elses work - but under the instruction of the senior electrician who advised me of the method he wanted me to use. I didn't get to see the CU at the house - only going on what I was told.

Why do I keep calling you TP - sorry about that!

 

Mr Sworld

Electrical Technician
Joined
Mar 21, 2008
Messages
1,152
Reaction score
0
I have been told to dress the cable so that a few cores of the SWA will reach the earth bar in the CU (sleeved of course) and trim and insulate the others off. I don't think this is right as I can't rely on the earth being continuous - not knowing how the joint was made. I'd have thought that either

a) a terminal box with a gland and banjo should be used or

B) all of the sheathes should be connected together (could group in three braids) and either put directly onto the earth bar.
Yes, all of the armour should be used. Any cutting away will reduce the CSA of the armour and, therefore, the CSA of the CPC.

Well done on being a member! (Hurr, hurr, hurr! He said 'member')

 
Joined
Mar 7, 2008
Messages
9,994
Reaction score
0
Location
In the office again.
Evenin` all.

I would agree with using all the swa strands - I`ve glanded & banjo`d of a pvc box previously; with no ill effects.

I hate to raise the issue, but query earth exporting.

As far as the unknown 3-2 joint is concerned; a continuity check SHOULD give you a good idea of the connection strength; under these circumstances, I would use 1 or 2 of the live cores to determine the length of the cable.

HTH

 

davetheglitz

Electrician
Joined
Mar 18, 2008
Messages
822
Reaction score
1
Location
Saltash, Cornwall
Hi Kme - oh the dreaded exporting of earths!

In this case there are no services in the garage and it's only 30 ft away - so as such exporting isn't a problem. more importantly it's not my job - so I don't have to sign for it (what a responsible sparky!)

I appreciate the SHOULD - but as then joint would be at one point of the cable I'm not sure a meter would be sensitive enough to pick it up.

Thanks for the banjo tip - in this case it's one of those detachable cover CU's so it's a bit of a no go. I've heard some people use piranha nuts - has anyone used them?

Dave

 

steptoe

of course Im wrong, ask my wife™
Joined
Feb 13, 2008
Messages
24,346
Reaction score
121
Location
Gtr Manchester
if your not signing it, and the guy that is told you to be a rough un then just do as he says and cut the armour down till it fits.!

I would do a cont check tho, just to confirm length of cable and cont of earth, and to double check the polarity.!!!

B)

 

Admin1

Forum Founder
Joined
Feb 6, 2008
Messages
10,278
Reaction score
-1
Piranha nuts

I bought one the other week, But haven't got round to fitting it. :(

 

Admin1

Forum Founder
Joined
Feb 6, 2008
Messages
10,278
Reaction score
-1
Dave - How long have you been an Electrician, Mate?

Do you specialise in Domestic, Industrial or Commercial?

 
Top