Shed in question is 10m away from house.
I was going to use armoured cable (6mm?) and just plug into socket in house and drill hole through wall. Route cable along garden fence, into shed, into plug socket.
In shed all I need to power is strip light and small freezer.
Is this safe to do? i.e. use plug socket. Or am I better getting electrician to do this?
and drill hole through wall. Route cable along garden fence, into shed, into plug socket.
I'd be inclined to patch into a fresh RCBO on the CU, or at the very least into an RCBO equipped spur.
Do you mean having a plug at BOTH ends of the cable? I hope not, but it is not, to me, 100% clear.
You could - although I'd be inclined to use a FCU (Fused Spur).
You *must* have the cable protected by RCD though.
I would have thought 2.5mm2 would be more than adequate at 10m length - I can double check this (current rating is fine at 13A max but volt drops are worth considering).
Plug into socket in house. Cable to garage going into socket. Plug into this.
Not cool?
Lost me :-(
So if I plug into socket in house (with RCD plug) this is OK? As you can see an electrician I am not....
an electrician I am not....
Yes, but you'd need to use a more sensible cable size, 6mm^2 won't have any chance of fitting a mains plug. Its not an ideal setup, but will do the job, with rcd protection.
NT
Can't see you needing 6mm for this...
In which case a circuit designed to support 13A of total load would be more than adequate.
If there is already a RCD[1] protecting the circuit, then fit a fused spur unit with a double pole switch. Drill a hole out the back of this through the wall. On the outside of the wall stick either a water prrof junction box or an external socket. Connect the SWA cable to this (2.5mm^2 two core will do) using an exterior grade gland[2]. Connect the junction box to your switched FCU with some normal 2.5mm^2 T&E cable. Run that to the shed and either repeat the trick with the junction box or take the whole SWA into the shed. Terminate that using a gland into a surface mounted metal clad double socket. Stick another metalclad switched FCU beside that with a 3A fuse in, and use that to power the light. (it can double as a light switch if you want).
Have a read through this:
chance of fitting a mains plug. Its not an ideal setup, but will do the job, with rcd protection.
No SWA cable will go in a mains plug. You need to join to a
1.25mm² or 1.5mm² flex to make the connection to the plug. Use a straight-through metal BESA box with an SWA gland in one side to terminate the SWA cable, and a 20mm cable gland to grip the flex on the other side. The BESA box needs to be earthed internally, to provide the earthing for the armour.I'd really have to question if the OP is going to be up to connecting this all up correctly, most particulary the earthing, given the questions. We haven't even discussed things like exporting earths or not, what type of earthing system the house is, what RCD protection the house has, how to split off the lighting circuit in the shed, etc. I would strongly suggest getting someone competent involved to do it or check it all out.
That's very simple
I'm not convinced any of that is particularly significant in safety terms
NT
Much cooler than the very dangerous bodge of putting a plug at both ends and using that to power up a circuit in the shed/garage. And not far off what I have done. We only need light, a fan and a laptop charger.
The house end uses a plug-cum-RCD.
Half the population would run a bit of extension lead down the garden in the grass or ties to rusty nails along the fence.
At least you are proposing armoured cable and RCD protection, so you're on the winning team to start with :)
It comes down to physics, and a bit of common sense:
1) The RCD will detect any fault to earth > 30mA and trip in less than 40mS- these are to do with the probability of the human body staying alive after such a shock.
2) The RCD will also give you enhanced fault protection for faults to earth- not wholly relying on the fuse to blow - this can be a problem with very long cables, but 10m is not that long.
3) You've only got a 13A circuit with a very low expected load at the other end.There are some deeply weird technical considerations to do with what they call "exporting the earth" from the house to an outbuilding, but these are only a serious concern with metal buildings where the house earth will be bonded to the metal of the building[1] or similar cases. Assuming you are talking wooden shed and not metal greenhouse, not really a problem.
Correction on cable size: I am not an encylopedia, so I checked:
Worst voltage drop is 3.26V which is neglible and the cable is fine for 13A.
I think the only remaining bit you may need help with is terminating the armoured cable and making sure the armour is bonded to the earth core at both ends.
You can use 2 core armoured and use the armour as the earth core (in fact this is typical) but there's not much in the cost and my incination is to go for 3 core because if one of your terminations is weak, you will not not lose integretity of the earth.
HTH
Tim
[1] Under some very weird fault cases, the house earth could rise to some highish voltage above the actual wet ground outside. Inside the house this is not a problem (mostly) as metal pipes and Class I (earthed) appliance all rise together due to the bonding - so there is no potential difference to stick yourselve across. However, if you cause your greenhouse to rise to 100V above the wet ground next to it, you have a problem.
I think the making off of the cable would be his biggest issue. It's not fantascially hard for someone used to doing minor electrical works, but I don't know what the OP is like.
There are pre-made kits which amount to basically the same thing, but all the connections are already done for you and it's all nicely sealed - which might be a good option:
Cheers,
Tim
Its a wooden shed so I guess I'm OK.
Plan is:- RCD plug in house Armoured cable runs through hole in wall Into waterproof socket via cable gland
Another armoured cable with plug on end. Runs 10m into garage Into normal socket box.
Am I right in saying that even if I use 2.5mm armoured cable I still might have an issue with the electrical connections? Its not as simple as standard electrical cable?
Would this sort of thing do?
No it's not.
Then you should bond both glands (one at each end) to the earth wire using a "banjo" tag (included) or Piranha nut (optional extra):
If you do not bond the armouring wires to earth, you gain no real advantage of using SWA cable.
Yep - at that price it would not be too much worse than amassing the bits.
All you need to do is bury the armoured cable the right way:
more than 2 (3 in a flower bed) spade's down is a good guideline, the soil must be free of large stones - either sieve a bit of soil back or line with soft sand.
Half bury, cover with supplied warning tape and complete burying (so tape is found well in advance of someone is digging).
Or you can put a line of bricks or paving stones over the cable route then the tape for extra robustness.
The leaflet suggests clipping the cable to a rank old wooden fence - do not do this, it is a crap idea - fences fall over. Brick walls are OK though.
But basically, your hardest job becomes the digging if you need to bury it.
You can't put a plug on the end of armoured cable. Firstly its too thick to go in the plug, and secondly you have no way of terminating the earth (armour wires).
See the link I posted elsewhere on SWA terminations.
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