Sub-mains needed?

[Lionscourt]

I was looking at a job today and ran across the following: 2-year old installation, 100 amp main fuse, Henley block next to the meter, with the main tails in and then out to the house. Along with this are three sets of 16mm SWA coming out of the Henley block (neutral and earth wires not properly colour coded) going off to various out-buildings. One of the cables goes to a garage with a full 17th edition board (there's a games room above, and a hot tub outside - it's a very nice garage). The owner wants some work done in this location.

Am I right that a sub-mains needs to be installed at the meter, with a maximum fuse size of 80 amps, and that I need to insist on this before I do any work?

 

[kingeri]

The way it is at present means the SWAs are not fused or RCD protected! Think of the CCC of 16mm SWA and then think they are only 'protected' by the 100a main fuse! Definately needs a secondary CU adding with appropriate MCBs, creating proper distribution circuits.

 

[Octopus]

I'd say the SWA cables do need to have MCB's or fuses protecting them...

 

[snowhead]

No single point of isolation currently either.

 

[mechelec]

No single point of isolation currently either.

Cutout fuse ?

 

[Amp David]

And how have these SWA been correctly glanded of into a Henley block?

 

[somersetsparks]

I'd go with a couple or 3 wylex 108M isolaters, you can gland into them properly, and IMO fuses are better for sub-mains.

 

[Guest123]

How much room do you have???

 

[Lionscourt]

Thanks for all your replies, I appreciate it. The cables come directly into the meter box, which is a standard plastic exterior wall box. They are not glanded at that end - the armouring is simply cut off a few inches into the box. The one cable whose other end I saw in the garage was glanded at the consumer unit.

There's obviously no room in the meter box for the Wylex isolators suggested by somersetsparks. The only thing I can think of that might fit in there is an MEM 800KMF, though I couldn't gland to that. Should the owner want all three cables properly fused I'm not sure 3 of those could even be squeezed in, or whether it's legal to do so.

I spoke to Napit tech support and they said I'd by okay to add a circuit to the existing garage unit as long as I wasn't making the installation less safe, but that I should recommend to the owner that the supply cable be fused at the meter end.

So, assuming the owner wants the extra work done:

Does the cable need a gland at the meter box, assuming it is properly earthed at the other end?

Can any necessary fuse units go in the meter box, assuming there is room for them?

I'm back there on Thursday so I'll see what happens when I explain this all to the owner.

 

[malcolmsanford]

Thanks for all your replies, I appreciate it. The cables come directly into the meter box, which is a standard plastic exterior wall box. They are not glanded at that end - the armouring is simply cut off a few inches into the box. That needs to be sorted and the SWA given mechanical protection as afforded with glands

The one cable whose other end I saw in the garage was glanded at the consumer unit.

There's obviously no room in the meter box for the Wylex isolators suggested by somersetsparks. The only thing I can think of that might fit in there is an MEM 800KMF, though I couldn't gland to that. Should the owner want all three cables properly fused I'm not sure 3 of those could even be squeezed in, or whether it's legal to do so.

I spoke to Napit tech support and they said I'd by okay to add a circuit to the existing garage unit as long as I wasn't making the installation less safe, but that I should recommend to the owner that the supply cable be fused at the meter end.

So, assuming the owner wants the extra work done:

Does the cable need a gland at the meter box, assuming it is properly earthed at the other end? See my reply above yes you should gland both ends

Can any necessary fuse units go in the meter box, assuming there is room for them? If there is no room in the meter box, and i'm assuming this is the outside type of box, just gewt a suitable metal clad lockable IP enclosure and piggy back it next to the meter box . Fit all the switch gear into , gland the SWA into it as well.

I'm back there on Thursday so I'll see what happens when I explain this all to the owner.

.....................................................

 

[somersetsparks]

I'd second malcolms point about a seperate enclosure, With the smart meters coming soon, they may make the customer have any equipment moved to fit their new meter in, after all no customers equipment should really be mounted in the meter box, especially not 3x switch Fuses, or even 3 x KMF's.