Dave-G Posted June 15 Report Share Posted June 15 My son in law asked if I could wire up a shed he's assembling in the back for his son to use an exercise machine, tv, computer etc about 25 yards ish away. Its years since I worked with armoured and I seem to recall we needed glands at each end of the cable into the consumer units. It'll have some 13 amp ring main sockets and lighting. He's a builder and has lecky friends at work that can check the installation and sign it off. Can anyone confirm if glands are required - and what size cable should be used please, I'm thinking a single 2.5 armoured feed should be plenty? Quote Link to comment Share on other sites More sharing options...
jeffgg Posted June 15 Report Share Posted June 15 Is the cable going to be buried cilpped round a wall/fence or overhead this will affect cable size. you will need glands and means of earthing the steel armourings Quote Link to comment Share on other sites More sharing options...
Yellow Bear Posted June 15 Report Share Posted June 15 2 minutes ago, jeffgg said: Is the cable going to be buried cilpped round a wall/fence or overhead this will affect cable size. you will need glands and means of earthing the steel armourings Whichever way, if he is likely to use a heater in there I would go larger than 2.5. Quote Link to comment Share on other sites More sharing options...
Dave-G Posted June 15 Author Report Share Posted June 15 (edited) Thanks so far - I initially thought underground but its going next to a fence so it seems prudent to clip it to along the lower part of that. I'll ask about a heater. I seem to remember father - a contract electrician, using a strand of the armour as an earth - but that may have just been using twin core across a farm yard. Does it need planning or building control permission? Edited June 15 by Dave-G Quote Link to comment Share on other sites More sharing options...
jeffgg Posted June 15 Report Share Posted June 15 (edited) 9 minutes ago, Yellow Bear said: Whichever way, if he is likely to use a heater in there I would go larger than 2.5. Thats the reason i asked how the cable was going to be run. I would be running a cable 6mm minimum fed via a 32a rcbo braker Edited June 15 by jeffgg added information Quote Link to comment Share on other sites More sharing options...
Stonepark Posted June 15 Report Share Posted June 15 18 minutes ago, jeffgg said: Thats the reason i asked how the cable was going to be run. I would be running a cable 6mm minimum fed via a 32a rcbo braker Agreed, given the effort of running the cable in the first instance, the small increase in cost in oversizing the cable, is normally more than justified later when additional load is required, even if it isn't anticipated at present. Quote Link to comment Share on other sites More sharing options...
Wilts#Dave Posted June 15 Report Share Posted June 15 If you’re going back to the Fuseboard with a dedicated circuit might be worth using a 6mm and putting it on a 32amp supply. But if you’re coming off a socket in the house put it on a fuse spur (13amp) and 2.5mm will suffice. You’ll need the correct glands as you say and earth the armouring via the banjo. Quote Link to comment Share on other sites More sharing options...
Dave-G Posted June 15 Author Report Share Posted June 15 22 minutes ago, Wilts#Dave said: If you’re going back to the Fuseboard with a dedicated circuit might be worth using a 6mm and putting it on a 32amp supply. But if you’re coming off a socket in the house put it on a fuse spur (13amp) and 2.5mm will suffice. You’ll need the correct glands as you say and earth the armouring via the banjo. I hadn't considered that - maybe I'm being to stringent. Would a regular 2.5 or 4mm twin and earth from a ring main socket suffice given it will be visible on the fence? The feed would be shorter if that power source is used. Quote Link to comment Share on other sites More sharing options...
39TDS Posted June 15 Report Share Posted June 15 I think your son in law should ask his electrician friends tbh. You sound like you barely have a clue and I don't mean to be rude when saying that. Better safe than sorry, there is a lot resting on this being a safe install. Quote Link to comment Share on other sites More sharing options...
Dave-G Posted June 15 Author Report Share Posted June 15 (edited) 51 minutes ago, 39TDS said: I think your son in law should ask his electrician friends tbh. You sound like you barely have a clue and I don't mean to be rude when saying that. Better safe than sorry, there is a lot resting on this being a safe install. No doubt he will but I figured it'd be good to ask on here too, I'm fully retired and like to help my daughter out a bit. He suggested taking the feed from a socket in the house but I took a punt that elf n safety has moved on from that simplicity, maybe not. The work isn't difficult or stressful, but I'm a bit forgetful these days so its better to refresh my mind is all. I got a bit confused about one reply suggesting 6mm from the fuse board or 2.5 from a 13A fused spur off a house ring main socket. Edited June 15 by Dave-G Quote Link to comment Share on other sites More sharing options...
Jonty Posted June 16 Report Share Posted June 16 I design data cabling systems, so I can’t quote the electrical regs, but the principles of using armoured cable to connect two structures are the same whether it’s a fibre optic armoured or an electrical armoured. The armour Is typically continuous along the length of the cable so it can act as a conductor so you definitely need to gland it at either one or both ends in order to provide an earth/ground for the armour. Your sons sparky mate would, I assume be doing the final terminations so he could sign off the work. I’d have a chat with him and find out what his preferred method of installing the cable is, I’m sure he’d be happy for you to do the donkey work getting the cable from one end to the other and just leave him to do the key/safety critical works. Quote Link to comment Share on other sites More sharing options...
Wilts#Dave Posted June 16 Report Share Posted June 16 16 hours ago, Dave-G said: I hadn't considered that - maybe I'm being to stringent. Would a regular 2.5 or 4mm twin and earth from a ring main socket suffice given it will be visible on the fence? The feed would be shorter if that power source is used. It would need to be in some sort of containment if you used standard cable, armoured definitely the one to go for externally. For just a socket and light though, a fuse spur off the ring main in the house would suffice in reality which could be wired in 2.5mm 3-core swa. Maybe run the cable in etc and get an electrician in to make the connections/glands off? Quote Link to comment Share on other sites More sharing options...
moondoggy Posted June 16 Report Share Posted June 16 Yes, you must use glands on both ends of armoured cable. Are you intending to spur off an existing ring or radial circuit, or direct from consumer unit? Your first thing is to establish what equipment is going to be run off the supply to determine cable size. Also, you must factor in the cable length to account for voltage drop caused by the resistance of the cable. If you are going directly from the consumer unit, then I would err on the side of caution and go larger cable and protective device. If you are going off an existing circuit within the house, then there is not much point in larger cable than 2.5mm as the run of cable must come off the existing circuit via a 13amp fused spur to prevent potential overloading of the existing circuit. Hope this makes some sense. Quote Link to comment Share on other sites More sharing options...
Dave-G Posted June 16 Author Report Share Posted June 16 Thanks for all the replies. I will have another chat with him to see what he can get from work colleagues etc that will match what he wants to run in the shed. I'll be doing the donkey work running the cable and fitting sockets/lights in the shed. Quote Link to comment Share on other sites More sharing options...
JKD Posted June 16 Report Share Posted June 16 I had this to do a couple of years ago. I ran the armoured cable [10mm iirc] from the house consumer unit out to the shed, fitted the shed fuse board, back boxes, external lights/socket,,,, the electrician did all the connections etc, including the RCD on the main consumer unit, which is necessary IMO, as if tripped, it'll only be that, not the circuit 'linked' into. As said above,,,, always over spec the supply cable, as you never know what will be 'plugged in' etc in the future. Hope that helps. Quote Link to comment Share on other sites More sharing options...
williamwansbeck Posted June 16 Report Share Posted June 16 Any outside power must be protected by a RCD or RCBO as a health and safety issue to avoid death by electrocution! Quote Link to comment Share on other sites More sharing options...
Dave-G Posted June 16 Author Report Share Posted June 16 2 hours ago, williamwansbeck said: Any outside power must be protected by a RCD or RCBO as a health and safety issue to avoid death by electrocution! Are you saying a fused spur off a ring main 13A switch socket isn't good enough these days? Quote Link to comment Share on other sites More sharing options...
williamwansbeck Posted June 17 Report Share Posted June 17 No it is ,but the ring main you are drawing on must be protected by a RCD or RCBO. Quote Link to comment Share on other sites More sharing options...
Dave-G Posted June 17 Author Report Share Posted June 17 4 hours ago, williamwansbeck said: No it is ,but the ring main you are drawing on must be protected by a RCD or RCBO. Ah, thanks for that, please forgive my error in reading that wrong. Quote Link to comment Share on other sites More sharing options...
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