electric supply to shed

[Con Owen]

Hi

Have dug a trench 750mm deep, 25 metres from house consumer box to shed. Laid in the 10mm armoured cable, protected it and placed warning tape, not filled in as it needs to be seen that I have complied with the requirements of part P. Now need to get the old consumer box (fusewire type) replaced with a modern split board. I have six double sockets (metal) to install (think I will increase to 10 on the principle you can't have too many) and have 4x6ft low energy florescent tubes to fit. The shed has an Apex roof, what do you consider the best way to hang the florescent tubes? I am going to have a garage consumer box in the shed, this will limit me to 40amps, probably a 16 and a 6amp mcb, any thoughts on this, eg should I go for a 6way consumer box? Is there a specific type of board that the consumer unit should be placed on? (the one in my garage seems to be a piece of blockboard with porcelain/ceramic spacers behind). Already phoned 4 electricians who advertise as Part P but not received any response, one who was not qualified said it goes mad at this time of year.

Cheers Con

 

[mrbingley]

Mine has two 5' tubes in the top of the apex & two 8' tubes at the eaves. Works well for me, the workshop is about 16' X 10'.

Chris.

 

[PowerTool]

I have a couple of ordinary incandescent bulbs in my workshop for "instant" light,and seperately switched fluorescents over work areas.
The fluorescents are screwed to the beams (about 7' high)
Also have a garage CU with 16A + 6A MCB,all RCD protected.
Have 4 internal lights and 2 external floodlights (on PIR sensors) running off the 6A lighting circuit.7 double sockets on a radial running off the 16A.
Workshop is approx 8'x16',sockets effectively mean that every electrical item has it's own socket and no cables trailing on the floor.
Depends what you are going to have in the shop as to whether you would need a 6-way board instead - if you are going to have anything that needs a seperate 16A circuit,then yes;if not,and you will be working on your own (never more than one or two things on at any one time) then probably not.

Andrew

 

[bobscarle]

I have a 8' x 16' shed with 4 florescent fittings fixed to the roof beams and a spotlight above the bench. Seems to give plenty of light.

I used an ordinary consumer unit (8 way I think) as this was cheeper than the "garage" item. It is still protected by an RCB on the incoming side. I also wanted to avoid having trailing leads so I fitted 10 double sockets around the walls.

Bob

 

[paulm]

Hi Bob,

I'm not an electrician but thought the RCB should be wired to protect the circuits in the workshop, not on the incoming supply.

The wiring between the main house fusebox and the workshop should be protected by an RCB on the main fusebox at the house end.

Least that is what I thought based on investigating myself on various forums a while back and is what my sparky did when I chickened out and let him do it !!!

Cheers, Paul.

 

[woodbloke]

I did all my own electrics before the new regs came into force. I have a twin consumer unit in the 'shop with a 20A RCD for the 13A ring main and a 5A RCD for the lighting circuit. My 'shop is 20'x 12' and all power kit runs off the ring main. Lighting is by 4 double 5' tubes with a 3' single tube over the bench. In addition I've got 3 clip-on adjustable spots, 2 on the bench and 1 over the Tormek- you can't buy these in the sheds anymore so car boots is about the only place you can get them - well worth it if you see them - Rob

 

[Con Owen]

Hi

Thanks Guys for your help. It has certainly given me a lot to think about. I shall certainly increase the double socket outlets to 10. I will use blockboard with ceramic/porcelain spacers behind on which to fix the consumer unit, unless I'm advised otherwise.

Cheers Con

 

[Adam]

Hi

Thanks Guys for your help. It has certainly given me a lot to think about. I shall certainly increase the double socket outlets to 10. I will use blockboard with ceramic/porcelain spacers behind on which to fix the consumer unit, unless I'm advised otherwise.

Cheers Con

I don't think this is working practice anymore. Best to ask a qualified spark or check a book.

Adam

 

[Con Owen]

Hi Adam

Will check out, as from what you say practice has changed regarding what a consumer box should be placed on. Basically what I am doing is placing the items where I want them and then will get an electrician to change my old consumer unit (it is rewirable fuses) to a modern split load one (already purchased an MK Sentry 12 way with RCD and mcbs)and do all the electrical work to Part P, that is if I can get one, as I said earlier phoned four left a message not one responded. Shall have to widen the field when everything is in place. Basically it appears to be a straightforward task. If I have to I will investigate in greater depth, undertake work myself and have building control officer check out.

Cheers
Con

 

[Stoday]

I have a new house built this year, with a double "garage" that was built as a workshop, with insulated walls and doors and floorwarming.

The workshop is fed from a 45A MCB at the house consumer unit, not RCD protected. This feeds an 8 way consumer unit in the workshop, which has a timer, 6A MCB for 7 6' fluorescent lights, 6A MCB for the door, 20A for the floorwarming and a 30 A RCBO for the sockets.

Lights have high frequency ballasts, to avoid stroboscopic effects. The supply to the workshop is not RCB protected because:
(1) That's only required by the regulations for portable appliances, i.e. the sockets.
(2) I don't want an earth fault to switch off all the power to the workshop which might mean I'm plunged in the dark with machinary still rotating.

This arrangement was installed by a NICEIC registered electrical contractor.

 

[CHJ]

....snip...
(2) I don't want an earth fault to switch off all the power to the workshop which might mean I'm plunged in the dark with machinary still rotating.
.

The first time I have seen someone mention this extremely valid point.

There should always be at least one lighting circuit directly powered from the main supply source in a workshop that is only "killed" by a guarded master switch. (In a home workshop one that a casual visitor can't flick off by mistake).

Even a low voltage/wattage (12Volt) Bulb run from a trickle charged battery could be a hand saver. I have one running off the same car battery that backs up my alarm system* . It also means a basic light is available in case of power cut.

*fed up with small battery life spans and false alarms when they fail.

 

[Adam]

....snip...
(2) I don't want an earth fault to switch off all the power to the workshop which might mean I'm plunged in the dark with machinary still rotating.
.

The first time I have seen someone mention this extremely valid point.

Its quite scary - it happened in my previous house as the incoming tails went straight into an RCD. My workshop had blacked out windows - so was absolutely pitch black. All I can say is you stand very very still. After you think everything may not be rotating, wait a bit longer. then a bit more. Finally carefull move you hands, and retreat away. In fact I got an emergency light that plugs in, and comes on when the power fails in the end.

Adam

 

[Colin C]

Thanks Guys

I will have to look at how mine are :shock: