Outbuilding Power

[JDLDIY]

Right, after having a minor wrestle with it this evening, I can offer up some more clues. The cable is copper, but with a paint layer on top which can actually be scraped with a screwdriver or your finger to show the copper underneath. The actual end of the cable where it joins the switch/fuse unit in the garage has an olive, then screws up to the box with what resembles a plumbers compression joint. Inside the joint the two tails are sealed by going through a gasket which is either made of bakelite or something similar. It's difficult to expose the cable properly without doing any damage. Both the tails are black in colour.

I'm beginning to think that this was installed when the house was built 40 years ago and that it is MICC. What do you think? Presumably if it is MICC I could leave it be? Would it be normal for this cable to terminate somewhere under my floor and for a normal cable to be run to the fuse box? I don't think the cable goes all the way to the onsumer unit.

Many, many thanks again

J D

P S Securespark I am pretty close to you but wouldn't want to bother you unnecessarily. When I get more time tomorrow can see if I can prise that olive a bit further down and try to identify 100%.

 

[JDLDIY]

OK, I wanted to post a picture I just took of the (slightly) dismantled cable connection in my garage in the hope that someone could identify it and I would be a step closer to finding out whether it needs replacement or not. I don't have a web page to host it on though as I have never wished to do this before. Anyone got any ideas?

 

[Big_Spark]

JD, here is your picture

The cable is certainly Pyro, and it has been well mullered. The end of the cable will require re-terminating, and the cable tested properly to ensure it is safe, this is not a DIY job.

 

[JDLDIY]

FWL, many thanks! How the hell is that done, you can no doubt see my code above, what did I get wrong? So is this MICC? The cable terminates in a junction box on the outside rear wall of my house, household connectors to what looks like power cable continue onto the CU. I want to get it protected by RCD. Do you think I would be best off to replace with SWA?

JD

 

[Big_Spark]

JD..no worries. The {img}image URL{/img} is the way to do it, simply replace the {} with [] tags.

Yes, Pyro is MICC.

I think you would be wise to scrap the Pyro and replace this with SWA straight from the Consumer unit to an enclosure in your Garage.

It might pay you to give Securespark a shout, Simon is in Stockport, not sure how near to you that is, but I'm sure he can help.

 

[JDLDIY]

Doh!! I was using the wrong page address - but I did it now, I AM a computer genius! Maybe not!

May well do that, thanks again

JD

 

[JDLDIY]

So I was just looking at the various types of SWA. Obviously I can understand the reason for differing core thicknesses but why would you want other than 3 core? I was thinking of using 4mm 3 core cable. What makes this a non-diy job if anything?
JD

 

[Big_Spark]

JD, 4mm SWA 3 core sounds about right, although considering the small cost difference you may be wise to up it to 6mm 3core as this give you greater load abilities if you wish to upgrade things later.

I would not recommend a DIYer tackle this sort of job, unless they have a lot of experience and know how to terminate SWA properly. You may not be relying on the sheath for the earth, but it does provide a vital backup if it id connected as if it were.

 

[JDLDIY]

FW, many thanks for the reply. I'm more than happy with the procedure required to terminate the SWA, have some good instructions on that. Thanks for the advice on the cable size, sounds like 6mm may be what I'll go for, I do tend to use the power tools quite a bit!!!
I've been looking for a straight forward swich/fuse unit though, can you recommend one? Screwfix' all seem to be RCD ones, but that seems pointless with the circuit being proteced from the RCD side of the CU in the house. Thanks again,
JD

 

[Big_Spark]

JD, for safety you should have an RCD either end of the cable.

Here:

 

[unphased_spark]

Just to add to FWL's point the reason he suggests an rcd at both ends is to provide protection for the cable leaving the house and for protection on the garage side of the installation (where you have made clear electrical equipment will be used)

 

[JDLDIY]

Hello again! Please forgive me for resurrecting my old thread, but I'm slowly getting around to this job. My plan for the installation so far is;
30A RCD/MCB in house CU
6mm 3 core SWA

To connect the SWA to the CU (modern Hagar plastic model) using the outer armor as additional earth, presumably I will need to run the swa to a metal junction box and from there to the CU with 6mm twin and earth?

After laying the SWA either in the metal conduit already in place or in fresh conduit (groans at the thought!) the SWA is ideally terminated at a metal clad garage CU. Here I have come unstuck as the local wholesaler (supposedly the largest independent according to the irritating marketing played over the phone system) doesn't sell any. Neither does Screwfix although they have a plastic Volex one on offer for a tempting £25. Has anyone got any links or suggestions for one? If not am I right in saying that I will need to terminate the cable at a metal junction box again and then run 6mm T&E to the Garage CU, which should have RCD?
So many questions but I'm off work with the lurgy so may as well get all the planning and purchasing done!
Many thanks again.
JD
PS I've seen this mentioned before here somewhere, mounting boards for CU's should be fire retardent according to my info, what constitutes that? In the house mine is a bit of old shelving laminated chipboard, don't imagine it would hold up too well in a fire!

 

[unphased_spark]

Try this link here

http://www.tlc-direct.co.uk/Products/CMM2N.html

As you are using SWA you would not need to bury it in conduit as mechanical protection is already catered for.

Mount the CU on MDF which has reasonable fire retardent properties, although mounting direct to the wall is perfectly viable.

Maybe one of the other guys can provide more fat in terms of what constitutes that.........

Lee

 

[JDLDIY]

Thanks Lee, that's a good link. Can't see any RCD protection mentioned though, so not sure it's quite what I'm after. RCBO is an option but that makes it expensive. I found 2 Contactum units on the same site specifically for outbuildings, but not metalclad. On screwfix there is a Wylex unit for £40 which is metalclad, that may be the way to go. The "norm" for these units is to be 2-way, 6A for lights and 16A for power. There is a contaktum unit which includes 32A power though. I had thought that the power circuit in the garage should be wired as a straight spur, I need 5/6 double sockets, would it be better to wire as a ring and would a 32A MCB be better for the job?
JD

 

[plugwash]

pyro is fine if well terminated you would probablly get a spark to check it out though