Workshop Electrics

[RBE]

Well not specifically layout electrics but a question for you electricians out there. I am currently going through my garden workshop build and will need a permanent feed into the building from the house. I know a fair bit about electrics but as the house is council owned I'm not likely to get away with any self install shenanigans.

 

The question is as my budget is ever nearing and not a lot left in it for an electrician is there a way that I can self install this safely and satisfy the council chaps? Can I install and have it inspected and signed off by a sparky at a cheaper cost, can anyone come around and do it for me for favours? Anything is on the table at this point really. I can't envisage anything more required than lighting and maybe 3 double sockets.

 

Any help welcome!!

[cliff park]

You could run it as an extension lead, with a 13A plug on the end. Plug that into a plug-in RCD and off you go. You would, of course, be limited on load. Modern lighting and the railway itself take very,very little. (Remember that 3A at 12V is less than 0.2 A at 240V ) The problem would be if you decide it's too cold in the winter and plug in a 3KW fan heater. With all your other bits it could get a bit lively.

[RBE]

Well yes exactly and I will be using power tools and such. Ideally it needs to be a proper job.

[steve W]

Before discounting the portable extension lead, how big is the workshop and how far from the available 13A socket?

 

Whilst a properly installed permanent supply is the long term way to go, providing the distance is not too great to give a big voltage drop, you might not have a problem with a portable lead, at least in the short term until finances build up. My modest 8x10 workshop (which has been insulated) is fine with a 2kW oil filled radiator in the winter and even this doesn't run at full power, so this will leave say a further 500Watt + for lights drill, lathes, railway, whatever and as pointed out, much of this is low power consumption and not all used at once.

 

Regards

Steve W

[RBE]

Its a 20ft x 8ft workshop about 2m from the outside socket. It is a purpose built fully insulated building so will hold heat well.

[steve W]

Its a 20ft x 8ft workshop about 2m from the outside socket. It is a purpose built fully insulated building so will hold heat well.

OK . This is double in size to mine so you might well need a bit a bit more heat, but switch it on earlier to get the building warm; once warm the thermostat will keep it in check. The outside distance from the socket to the workshop is not significant - I assume that is 2metres and not miles!

A good quality short extension such as Toolstation part 71700: 5m x 2gang, can provide power that can then be used to supply your requirements up to the 3kW limit. The circuit arrangements of the existing outside socket should be checked and should be of a type that can be used in all weathers (not just having a weatherproof cover for the socket itself).

I would also strongly recommend that a 30mA RCD is also installed in the workshop at this time, regardless of what is on the existing house supply and in the longer term a permanent supply arrangement should be made.

 

Hope this helps.

[RBE]

Cheers for that Steve. Where would I stand when it comes to wiring in the actual workshop? I would obviously not want to have cables strewn all over and I'd like the lighting in when I do the dry lining. Can I do that myself and fit a distribution board in there that I can initiallt feed off the outdoor socket spur and then switch over to a proper feed later or does that have to be done by registered electrician too?

[steve W]

Cheers for that Steve. Where would I stand when it comes to wiring in the actual workshop? I would obviously not want to have cables strewn all over and I'd like the lighting in when I do the dry lining. Can I do that myself and fit a distribution board in there that I can initiallt feed off the outdoor socket spur and then switch over to a proper feed later or does that have to be done by registered electrician too?

It would be sensible to install cables during the build, but be aware that sheds/workshops as an outbuilding are considered 'special locations' and permanent work requires to be designed (especially earthing requirements), carried out/tested and certified appropriately to avoid any shadow of doubt or potential fine. For this you will need an electrician who is able to tick all the right boxes and provide you with a certificate. It's a much less painful way than trying to personally negotiate the bureaucratic minefield that these type of installations can become. You may be able to find a local electrician who will allow you to do the basic installation and he will certify it but I suspect the cost saving will be minimal. If you install cables yourself that are going in behind panels, they must be inspected before being covered.

Equipment plugged into an extension lead and disconnected when not in use should not cause any problems.

[edcayton]

It has been my experience that even good quality 13A extension leads have a habit of cutting out on frequent occasions even with a load of much less than 3kW.

 

My son has just had a quote of £100 to install a 13A feed to his new summerhouse which is about 3m from the house. That included cable, 2xtwin sockets and an RCD. Admittedly in Cornwall where labour costs are lower, but I thought that was quite good.

 

Ed

[steve W]

It has been my experience that even good quality 13A extension leads have a habit of cutting out on frequent occasions even with a load of much less than 3kW.

 

My son has just had a quote of £100 to install a 13A feed to his new summerhouse which is about 3m from the house. That included cable, 2xtwin sockets and an RCD. Admittedly in Cornwall where labour costs are lower, but I thought that was quite good.

 

Ed

Yes, very good. You've just given me another reason to move back home!

 

On extension leads, keep them as short as possible and keep the wire size up. There are many dubious ones out there, often with small cable and rated at 10A by fitting a smaller fuse in the plug. 

Source from a proper electrical supplier or a local wholesaler. MK-Duraplug 4way ones are good but pricey . They come with cable or without. If buying without, use 1.5mm2 for the cable. The pre-wired ones have 1.25mm2 - OK for 5m or so runs.

Cheers.

[Crosland]

It has been my experience that even good quality 13A extension leads have a habit of cutting out on frequent occasions even with a load of much less than 3kW.

 

What is there in an extension lead to "cut out"? If you mean an RCD plug, or socket, then that's a different issue to loading and should be investigated with some urgency.

 

Drum/reel type extensions are only rated for maximum load when fully unwound. Otherwise, cable heating can cause them to self destruct.

 

Andrew

[cliff park]

The thing with extension cables is to regularly check terminal tightness at both plug and socket end, where accessible, and if not moulded. They are more prone than anything to coming loose because of the handling, unreeling, reeling etc. As Crossland says they must be fully unreeled, especially when carrying an appreciable current.

[Suzie]

This is where bureaucracy gets in the way of doing a good job. If you can get permission to get a proper connection in to the house consumer unit with a 4mm² cable to your outbuilding with its own consumer unit properly installed by an electrician, or suitably supervised then that would be ideal.

 

If that is not possible your only practical solution is is to make do with plugging in to a suitable socket within the house - typically a 13A socket. In this case it will probably be best to make an extension lead with 2.5mm² round 3-core cable which is readily available and can be easily terminated in a 13A plug and terminated in fixed sockets in the outbuilding. Lighting can be fed via a 3A fused spur. If 13A is insufficient for everything (and if you need serious 3KW heating it probably won't be) just run a second cable with a second plug with a dedicated socket for, or wired into, your heater. Clip the cable neatly or protect it in ducting and it should serve well. This solution is protected by the fuse(s) in the plug and a plug in RCD in the house if the house is not already fitted with one and being unpluggable is outside the scope of fixed wiring regulations.

 

Use only LED lighting to maximise the amount of power available for other things. 2.5mm² cable is considered good for 18A nowadays so should be OK with a 13A fuse, but smaller cable as typically found in ready made extension leads might be pushing it.

[RBE]

I've spoken to the council and I can connect to the house mains however I do have to have the work don't be a fully qualified electrician who will sign off the work done on the councils forms. No biggy really. The issue is I don't have the funds in the budget to do it straight away. I will need to source a cheap one locally.

[vitalspark]

OK there's only one proper way to do this and its not complicated.

The regs have been tightened up considerably so what you need first is a proper supply from the house to the shed.

This can be either an SWA (Steel Wire Armour) cable buried in the ground or an overhead with catenary.

The former is the preferred method very easy to dig only needing a very narrow trench really with the edge of a spade.

Buy 3 core 6mm/sq swa cable.

Its cheap enough at less than £3/metre plus you need a gland pack for each end another £10 tops.

This is where it gets tricky as although its dead easy to make off the glands unless you are shown you probably won't manage it.

 

Assuming you have your supply installed you now need a fusebox in the shed.

This provides a means of terminating the SWA cable and splitting to the 2 circuits for lights and power.

You need to buy a 'Garage Board'..thats what they are called.. and consists of a compact fusebox with RCD main switch and 2 circuit breakers.

Make sure you buy one with a 40 amp rated main switch and not a 63amp as many are.

Reason for this is you are supplying with a 6mm/sq cable and this cannot carry 60 amps but ok for 40amps.

Even if you are only planning to use a light and the odd fan heater fan heater it doesn't matter as the regs insist that the main incoming supply must be capable of supplying the max the main switch is rated at..so go for a 40 amp unit which will be cheaper too.

My warehouse sells them at less than £30 incl vat and thats a decent and robust board.

Wire the sockets as a radial circuit if only a couple and the light is self-explanatory.

At the house end the SWA is terminated at the main fusebox and connected to a suitable circuit breaker.

It is desirable to have the actual cable protected by an RCD device but if you don't have one within your fusebox you can replace any mcb with an RCBO.

An RCBO is a miniature circuit breaker (mcb) with an RCD built in.

Unlike an RCD it also protects and breaks the circuit if an overload or fault occurs..a straight RCD will not do this.

An RCBO is different and can be used as the sole means of protection and load/fault breaking.

Of course if you have an RCBO or RCD /mcb set up at the source you don't need the same at the shed however I find that the easiest and most convenient and usually cheapest means of terminating and distributing is the 'Garage Board' as an enclosure with a main switch and 2 mcbs usually works out more expensive.

At the end of this you need to have a test carried out which is pretty straightforward and includes a loop impedance test done to prove that the earth is actually good enough to pass fault current and not just sufficient to illuminate a test lamp.

All sounds a bit complicated but it isn't and tbh its a very straightforward and routine job for a spark.

Any registered electrician will have calibrated instruments and the Loop Test is a plug in and press button job.

I live in the west of Scotland so a bit too far for me to travel but it sounds like you need this installed properly so my advice is contact a registered electrician.

You can ask him how he would go about it and if he deviates from my suggestions..SWA cable and RCD protection or Garage Board with a test at the end of it..then you have the wrong guy.

 

Hope this helps.

 

All the best.

 

Dave.

[14Steve14]

240v can kill if not worked with properly. If you don't know what you are doing, leave it to someone that does. My parents had a shed fully wired with lights and a few sockets and it only cost a few hundred pounds including the vat for the labour and the parts used. The wiring got signed off by the electrician. If you run any of the wiring yourself, it will take longer for someone to check it all thoroughly before signing it of. Who ever signs it off, is legally responsible for it, so will have to make sure its all done properly.

[Junctionmad]

if you are really tight on budget then make up your own high quality extension lead, RCD plug at on end , good quality 2.5mm2 outdoor cable , rubber or ARTIC.  then on for more distribution sockets sets . 

 

worked in my garage for years , including  table saws, compressors etc 

[RAF96]

if you are really tight on budget then make up your own high quality extension lead, RCD plug at on end , good quality 2.5mm2 outdoor cable , rubber or ARTIC.  then on for more distribution sockets sets . 

 

worked in my garage for years , including  table saws, compressors etc

 

Continuing the extension lead scenario - go down your local caravan accessory shop and buy a ready made outdoor capable 240v extension lead as used to hook up touring caravans to the pitch supply, usually 25m of orange heavy cable.

 

These come with various live end plugs or adaptors including a 13amp house plug. The other end has a blue connector that would plug into a matching connector at the shed.

 

All the above providing you are capable of wiring up the shed and its connection to a safe configuration.

[Suzie]

Not all blue plug caravan cables are made to the highest standards. Some are not very rugged and need to be treated with extreme care! Like all extension leads there are a variety available from the not much good to high quality.

[RBE]

Well the budget has dried up so will certainly be working off of an extension for the first few months at least. I am able to do wiring (I know what to use and where etc) however the council won't allow me to do so so have to get a qualified electrician in to install and sign off the work.

[dhjgreen]

Something like this may be more suitable than a caravan lead. Just chosen at random from a search I know nothing about the quality or price competitiveness.

 

https://www.norwichcamping.co.uk/shop/product/sunncamp-mobile-mains-power-unit-ma5050-2059/?gclid=Cj0KEQjw4fy_BRCX7b6rq_WZgI0BEiQAl78nd85Z5-w8Yi_hTxfipnv_4gtjeeHXAhp33vjPiydT3NIaAsxD8P8HAQ

[m.levin]

Have a look at this site, for cable.

 

https://www.tlc-direct.co.uk/Main_Index/Cable_Index/Flex_Artic_Yellow_or_Blue/index.html?ad_id=11956697645&source=msn&kw=17443739051&matchtype=e&f=b

 

Get a plugin RCD, put a plug on one end of the cable and a waterproof double socket on the other end. then just roll it out when you go out to play.

 

If you are not sure, just get someone competent to work with your Electrics. 50v 1/2amp is enough to put you in a box, depending on the age and condition of you consumer box and supply voltage you could be looking at 250v - peaking above 32amps!

the country is full of DIY electricians, if they all did it correctly and safely, domestic electrical work wouldn't need signing off, so if joe bloggs down the pub offers to do the work for you, be sure he really knows what he is doing. 

[Crosland]

If you are not sure, just get someone competent to work with your Electrics. 50v 1/2amp is enough to put you in a box, depending on the age and condition of you consumer box and supply voltage you could be looking at 250v - peaking above 32amps!

the country is full of DIY electricians, if they all did it correctly and safely, domestic electrical work wouldn't need signing off, so if joe bloggs down the pub offers to do the work for you, be sure he really knows what he is doing. 

 

Sorry, but I would have to apply the same maxim to your own advice.

 

The fatal current is a lot less than 500 mA and 50 V can be just as fatal as 500 V. As with most things in life, individuals will react differently and some will survive where others are killed stone dead.

 

The fact that a mains circuit may be capable of supplying 32 A (or even more) is irrelevant.