Can anyone identify this cable?

3 Aug 2008
Reaction score
United Kingdom
Hi all. I'm planning to upgrade the wiring in the garage but, before going any further, want to identify the incoming cable to check its capacity etc.

Garage is about 6 metres from the house, built and wired some 25-30 years ago. The cable (buried) is twin core and shrouded in a semi-rigid orange sleeve (aluminium?) which also acts as earth.

The two current-carrying wires are both black and are factory printed all along with what looks like "STUB SLV 7 & 7.5mm2". The printing is not clear. Those 7's could be 1's but the wire is far too chunky to be 1 or 1.5mm. What's all that about?

I've Googled like crazy and can't see any reference to this product. Can anyone help? Also, how is earth-shielded cable viewed these days?
Sponsored Links
How chunky is 'far too chunky'?

It sounds like MICC. 2L1.5 is something like 7mm in diameter.
orange plastic protective covering over semi-flexible copper tube, maybe? it is fireproof but not armoured. And expensive to buy and to work with. Who do you think installed it?

a picture, especially of what it is connected into, would help a lot..What is the diameter, compared to a pencil?

do not cut or try to joint it yourself, if moisture or humid air gets in it will be damaged
Cheers JohnD. I've investigated further and you're absolutely right. It's a copper casing covered in a plastic orange sheath.

The diameter is almost exactly that of a pencil, a bit less if you disregard the sheath.

I'm beginning to wonder if the "STUB SLV 7 & 7.5mm2" is actually a sleeve (SLV?) for the bare wires in the junction box and is giving a false impression.

Monkeh, the picture in your link to MICC is almost certainly what it would look like cross-section. I hope it's not 1.5mm wire. Does the pencil size make it likely to be any beefier? Then again, I see that MICC can be uprated because of its fire-resistant properties.

It was probably installed by the builder who built the house for his own occupation. He did use some unorthodox materials elsewhere.

The ideal solution would be to inspect the wire itself but it's rather inaccessible and I was hoping for clues from an external view.

Any more thoughts?
Sponsored Links
It is much more likely to be 1.5mm than 7.5mm. How about those photos?

how much power do you want to put through it? I'm not good on MICC but it will probably take more than 20Amps
Bit late for photos! I'll take one tomorrow.

Power-wise, I did want to run an electric heater and other stuff and was planning on rewiring as a ring with a 32A garage consumer unit.
Will do tomorrow when I've cleared a space to get at it properly.

Thanks a bunch, guys.
If you look at a gland or pot it should have the number of cores and the size of cable engraved into it for example 2L1.5 is 2 core, light duty 1.5mm conductors.
Eureka! It's on the gland - 2L1.5, clear as daylight with the cover pulled back. Also managed to release a wire to see the copper and compare with known 1.5mm. It's definitely the same gauge.

So, looking at MICC table 4G1A, the cable is good for 23 amps. This scuppers my plan for a ring with 32A CU. (Currently it's an old hot-wire fusebox.)


1. We need all the available capacity as I plan to make the garage a decent little workshop. If I buy a 16/6A garage CU (looking at MK - good deal on Screwfix), can the 16A MCB be swapped to 20A? (i.e do these units use standard MCB's?) Lighting will not take more than 2A.

2. Is is still worth re-wiring the garage as a ring, in case I get the chance to uprate the supply cable later?

3. Why do they not supply garage consumer units as split load when a workshop scenario is where you are most likely to want lighting when power trips?

Fantastic responses, guys. Thank you so much - and sorry for the false trail earlier on. The junction box was hard to reach until I cleared the clutter.

PS. Yes, I will get sparks to do the work but like to have head full of info before engaging him, having been seen off before.
if yopu have an old fusewire box in the house, take this an opportunity to start replacing it. It is not a DIY job. If the garage submain is fed entirely in armoured or pyro, you can use an RCD in the garage and not in the house

1) let the electrician supply and install.

2) if you want but unlikely to be necessary. The cable from house to garage will not be a ring, but a single cable (a sub-main)

3) You can ask him to price for RCBOs per circuit which will avoid that problem and is a better solution. Ask him to get a box with some spare ways for future expansion, and a good brand like MEM or Crabtree, not a budget one from a discount DIY shed.
Thanks, JohnD.

Yes, the house has an old fusewire box which I've long been meaning to get replaced. No, I wouldn't dream of doing it myself!

Do we really need RCBOs on the lighting circuit? Overkill at that price?

I was thinking of a 2.5mm ring in the garage if we eventually upgrade the supply cable to 4mm SWA (roughly similar load ratings) as I may need more heaters. Is that a problem in theory with a sub-main?
you indicated that you wanted the lights to stay on if the sockets tripped. RCBOs will do that. And vice-versa.. If you have RCBOs you will not need an RCD as well. My house is crammed with them.

You can have a garage ring if you want, but I would not feed it from your old fusebox.

Several heaters will drop the voltage in your garage a bit.
Yup, all is clear. In a garage unit the RCD acts as the incoming isolator for both circuits, right? I was just wondering what would be wrong with a CU made of

- 2 pole switched isolator
- Power circuit with MCB and RCD
- Lighting circuit with MCB only

which would, I guess, be more economical than all RCBOs? Does that configuration also required a switched incomer?
the cost of one more RCBO should not worry you.

you do need a "main switch" in the garage CU

you also need a DP isolator, or a switchfuse if it is not taken from a spare fused way on the house CU, inside the house to cut power to the garage cable.

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Sponsored Links