Armoured Cable for Shed

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Reply to
John Rumm
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A lot of that depends on copper prices. TLC seem to update theirs more frequently, so they're expensive in a rising market, cheaper in a falling market. I'd suggest checking Discount Electrical too.

My Toolstation & Screwfix are 40 miles apart, in opposite directions, with Machine Mart & TLC somewhere in the middle. Shopping is more a question of which direction I'm going in than detail pricing.

Reply to
Andy Dingley

I believe that extension leads arent covered by part P so you could have an rcd plugged into a socket in the house, then an extension lead going through an underground pipe and coming out at a socket in the shed.

Im Not sure about moisture though.

Personally iv put in an earth spike with a wire to earth, and also have earth coming from the shed, which may be illegal but it feels safe to me

[g]
Reply to
george [dicegeorge]

Get a battery backedup emergency exit light so when the elec trips it comes on.

I have several.

[g]
Reply to
george [dicegeorge]

Many of us have our NAS boxes or servers in the shed. (well I do)

Tim.

Reply to
Tim..

Might be useful for:

- intruder alarm

- doorbell extension

- intercom to house

depending on what you are getting up to in the shed. Intruder alarm in particular if you have any nickables in the shed.

Owain

Reply to
Owain

Been busy elsewhere today...

1 - Running a shed off an internal circuit.

Possible where 1) shed load is a socket & a light and 2) house final circuit is lightly loaded and 3) the shed is wood on wooden sleepers above ground with no class-1 tools outside (re exporting PME).

Whilst possible it is much better to do it as a dedicated circuit or submain.

2 - Exporting PME

You can export PME to shed which is wooden, on wooden sleepers on ground, with no class-1 tools outside, no incoming services and no other extraneous steelwork introducing a potential inside.

If the above is not true, exporting PME is problematic because you need to bond whatever in the shed back to the house MET in 10mm cable (possibly, same as MEB) or 16mm (more likely, not checked) which is hassle. Worse, there is an argument you need that concentric with the cable which might mean a jump in SWA size (not checked, 17th added some different wording w.r.t. this).

For practical purposes you would just TT the shed, much simpler.

3 - Checking on 17th re cables sharing duct

I will need to check, but it must be fine if segregated. I can not recall if there was a new clause.

4 - SWA prices

Not all SWA is the same from experience, check what the brand is (or duct it if any doubt). I think Screwfix carry Prysmian in 25m lengths which is the best (unless you like AEI which tend to go to the top of every spec re armour diameter, cable diameter, sheath etc). However TLC SWA CW glands are better than Screwfix (ok, just a bit flimsy on the smaller sizes, at least the threads aren't tapered!).

5 - Multiple RCBO at shed end

This is typically done where you want a socket trip not taking out the lights. The problem is it leaves you with non-RCD protected cable from the shed to the house - you either route SWA to the CU or ugly surface run or supply the outside jn-box to SWA in BS8436 cable. The problem is BS8436 doesn't go very big in conductor size - however the prices do per 100m!

For practical purposes RCD (submain) or RCBO (final circuit) at the house end with an emergency light in the shed. Not expensive, you want "non-maintained" as most people want it off until the power fails.

6 - Running flex thro conduit to shed re Part P

Do it properly :-) The only way to make this work would be uncoiling an Arctic or H07RNF cable to the shed each time you need it. That gets into BS4343 CEEFORM Interlocked Sockets re domestic unshuttered and getting a large enough cable in which is =A30.89/m for 2.5mm H07RNF. Running flex underground is a no-no, it's not designed for continual submersion and has no protection whatsoever.

Will check on 17th later - I believe the wiki was updated re bonding any shed services etc back to MET?

Reply to
js.b1

and a mail server.

Reply to
dennis

In message , Tim W writes

Battery backup emergency light (the type that lights when the mains fails) then..

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Reply to
Clint Sharp

Part P applies for any permanent installation, regardless of how the final connection is made.

Multiple earths are allowed under PME (its in the title!) - but its hard to see what you would gain (the same issue about exporting the main equipotential zone would apply). It would be ok under TT, less desirable under TN-S. If you are going to the bother og having a local earth connection, then its far better to make the shed a TT install, and only use the exported earth to protect the submain (which is isolated from the shed earth at the shed).

Reply to
John Rumm

Switching my welder on occasionally trips the MCB on my shed socket circuit. I didn't own a welder when I designed the shed supply, but I'm very glad I used separate circuits with all protection (except for the cable itself) locally.

Pete

Reply to
Pete Verdon

?

I've only done a couple of cables, but simply used a pair of sidecutters on the armour wires with no difficulty in cutting or in fitting glands.

Pete

Reply to
Pete Verdon

Pete Verdon wibbled on Tuesday 15 December 2009 02:47

In which case, it's also worth designing the system to accept a type C breaker (slightly lower L-E loop impedance required). That would help.

Reply to
Tim W

Easy enough to cut, but to get access for sidecutters in there you have to splay the wires open a bit. So long as you're careful and neat here it's OK, but if you bend them every which way it's hard to smooth them out to get the gland back together over them.

DIY one-off, just take your time. Commercial job and the wages clock is runnning.

Reply to
Andy Dingley

Yup, that is one possible solution. There are no hard and fast rules here - much depends on circumstances as to what level of interruption to power / lighting is going to be acceptable.

Reply to
John Rumm

They wouldnt be in the same duct

NT

Reply to
NT

So many have said much the same, but give it a few years and often one's wishes expand. Cat5e can be used for a wide range of apps, not just computer networking. Sticking some in the same trench only costs a couple of peanuts, no need to terminate it.

NT

Reply to
NT

True - it's a standard small CU so I could easily replace the MCB with a type C one. But trips are rare enough that I don't think I'll bother. Thanks for the idea though - hadn't occurred to me for some reason.

Pete

Reply to
Pete Verdon

or using a DIN mounting cartridge fuse holder in place of the MCB...

Reply to
John Rumm

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