Size of supply cable

[Stratocruiser]

My consumer unit and meter are in one cupboard but the main supply fuse is on the other side of the house. There is a copper covered cable which goes under the floor and joins the supply to the meter. This has two wires covered in black insulation which come out the end of it, and go into the meter. The earth connects to the outside of the cable.

What is bothering me is that there are great big thick cables from the meter to the consumer unit, but the ones going into the meter are a lot smaller. The black insulation has .01 BICC .0145 printed along it. Can anyone tell me if this is the cable size and what it means? And should I be worried about it being small?

 

[Lectrician]

Photo would be great.

 

[ChrisRogers]

sounds like MICC, so a smaller size would be expected, just how small it actually it is the question.

 

[Stratocruiser]

Sorry, not got technology for a photo.

It is hard to tell as I can't see the metal inside. The black insulation on the two wires coming out is rubbery and seems a bit loose fitting. Not perished or anything, but quite stretchy. So it is hard to say even exactly how thick the wires are even with insulation. But the whole thing including metal outer seems about the same as the 25mm with two layers of insulation coming out of the meter. Which means it must be way smaller.

I was wondering if the numbers on the cables might be imperial sizes?

 

[Paul_C]

The numbers do indeed correspond with the old 0.01 and 0.0145 sq. inch Imperial sizes. The black insulation will feel a little loose as on MICC cable it is sleeving which is added during installation rather than being an integral part of the manufacturing process.

Can you see any markings on the cable itself to show the size?

The basic ratings, as per 14th edition IEE Regs. (the last Imperial edition) are 68 amps for 0.01 sq. in. and 85 amps for 0.0145 sq. in. (You can add a 6% correction factor if ambient temperaure is below 25 deg. C / 77 deg F).

 

[Stratocruiser]

Ah thanks. I guess that explains why the insulation has two numbers on it. If it is designed for either size of cable.

Might be able to measure the diameter of the whole cable, but really don't fancy squeezing the individual wires in the blades of some calipers. The outer has been painted so I dont expect I will find anything written on it unless maybe it is embossed.

I make it that means the 0.01 in size would be 6 square mm current size. Feel a little more reassured.