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Workshop wiring query

W

Wizard9999

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Mike

As you know I treat your build as the definitive source of info. As I am now thinking of electrics I've searched the thread but can't find any mention (both skimming over it again and using the advanced search function on the board). Did miss something?

Looking at the pictures from the tour it looks like the cabling to sockets, etc. is all surface mounted. Is this correct?

Thanks,
Terry.
 
Hi Terry.

Yes, all my cabling is on the surface. That's the safest way....no danger of screwing or nailing into the wall and hitting a wire. Just make sure to run all your cables horizontally or vertically, with plenty of cable clips.

The reason I didn't post properly on the electrics is that it is incomplete. At the moment, the power supply to the workshop is via extension lead, and I have no consumer unit. When we run a proper cable out there in the spring, I'll get an electrician to fit the consumer unit, the earth spike, and do the testing and certification.
 
I put all my cabling in plastic tube conduits and are also surface mounted. I reasoned that if I ever want to reconfigure the workshop it would be easy to move.
 
thinking about it Terry...even my garage has the ring main surface mounted. The cables are inside a circular plastic trunking which I agree with the last poster is neater than just bare twin n earth. The sockets are those box jobs that are the opposite of flush fit. (All doubles)

It seems that's the right way to go and then there's no worry about accidentally nailing anything either. Its a lot easier too.
 
Rob":22suhee7 said:
It seems that's the right way to go and then there's no worry about accidentally nailing anything either. Its a lot easier too.
Click to expand...

Unless you are trying to get a ring through 20mm circular conduit - getting 2 cables down and round bends can be a nightmare and almost requires a bit of lubricant (washing up liquid) if you cables are in any way twisted - especially over long spans (DAMHIKT). Bit more expensive, but the square trunking with the snap on top cover is a lot easier to fit!
 
If you're putting your cable in trunking, use individual strands, not twin core and earth. Much more flexible and easier to pull.

Mark
 
the bear":1gu5jffz said:
If you're putting your cable in trunking, use individual strands, not twin core and earth. Much more flexible and easier to pull.
Mark
Click to expand...

I found that out the hard way. In some instances I actually stripped the individual strands out of the cable.
 
Morning all

Conduit is really designed for individual wires. The rectangular section of trunking is better suited to T & E.

With a little care you can get three 2.5 mm T & E cables in the 16mm x 25 mm stuff.

Steve, you are right about the twists, but I'd suggest talcum powder as a lubricant. Apart from the mess, I don't know what washing up liquid does to the insulation.

Cheers

Dave
 
Have to confess that I simply surface mount where necessary (or in the case of my workshop treated the cabling as you would in a house ie in the cavity 'safe areas' of the walls). Trunking is a bit to pricey for me especially when you add in all the wee connectors and right angled joints.
 
StevieB":1i9dbiup said:
Unless you are trying to get a ring through 20mm circular conduit - getting 2 cables down and round bends can be a nightmare and almost requires a bit of lubricant (washing up liquid) if you cables are in any way twisted - especially over long spans (DAMHIKT). Bit more expensive, but the square trunking with the snap on top cover is a lot easier to fit!
Click to expand...

Foregive my ignorance, DAMHIKT means?

Oh and sorry Mike, I appear to have hijacked your thread!

Terry.
 
OK, now I have a proper thread for this, I'll push on further.

Power will be coming from the main house supply with a dedicated consumer unit (or whatever it is called) in the workshop. There will be a facility for isolating all the power in the workshop from inside the house just in case my children decide showing their friends how easy it is to remove fingers! I am planning 18 double power sockets (13A I guess) and three single 16A (or should it be more) sockets for tablesaw, possibly planerthicknesser (don't know yet as I haven't bought one so far) and a bit of future proofing. I plan to have six double flourescent lights in the ceiling as well.

As I have no experience of anything electrical and will have an electrician doing all the connections, etc. But want to do all the cable runs myself, as much as anything else so I can fit it around everything else I am doing on the workshop. I have a number of questions, which are no doubt basic to many others, but are far from it for me. Any help would be much appreciated.

1. How many of the 13A sockets can I reasonably run on a single 'ring', all of them or will I need to split it?

2. I assume the lighting circuit can be one separate circuit, correct?

3. Also the 16A sockets on a separate dedicated circuit I guess?

4. I understand 2.5m sq cable it typical for a ring main for 13A sockets, any suggestions on what should be used for the lighting and the 16A circuit?

5. does it matter where in the lighting circuit the switch is, does the cable have to go to the switch first, or does the switch simply 'break the circuit, so it doesn't matter where it is?

As you can see, I need some help!

Terry.
 
Wizard9999":2sjcs01m said:
OK, now I have a proper thread for this, I'll push on further.

Power will be coming from the main house supply with a dedicated consumer unit (or whatever it is called) in the workshop. There will be a facility for isolating all the power in the workshop from inside the house just in case my children decide showing their friends how easy it is to remove fingers! I am planning 18 double power sockets (13A I guess) and three single 16A (or should it be more) sockets for tablesaw, possibly planerthicknesser (don't know yet as I haven't bought one so far) and a bit of future proofing. I plan to have six double flourescent lights in the ceiling as well.

As I have no experience of anything electrical and will have an electrician doing all the connections, etc. But want to do all the cable runs myself, as much as anything else so I can fit it around everything else I am doing on the workshop. I have a number of questions, which are no doubt basic to many others, but are far from it for me. Any help would be much appreciated.

1. How many of the 13A sockets can I reasonably run on a single 'ring', all of them or will I need to split it?
In theory as many as you like. You are limited by the total current determined by your breaker. So you need to think what you might be plugging in and running at the same time. A 2kw heater will consume 8A, for example. Then do the maths and if you think you might be getting close to your breaker rating then you'll need to put in a second ring circuit. There is one school of thought that advocates a separate ring for things that you want to keep running all night (say, a vacuum pump) and then to have a master breaker that kills everything else in the workshop. Probably overkill for a small workshop.
2. I assume the lighting circuit can be one separate circuit, correct?
Yes but again depends on what wattage lights you will be running. A lighting circuit is rated at 5A
3. Also the 16A sockets on a separate dedicated circuit I guess?
Not quite. If you are going to be running two machines at the same time and both need a 16A supply then you should think about having a separate radial circuit per socket. Having said that I haven't done that in my workshop
4. I understand 2.5m sq cable it typical for a ring main for 13A sockets, any suggestions on what should be used for the lighting and the 16A circuit?
The same

5. does it matter where in the lighting circuit the switch is, does the cable have to go to the switch first, or does the switch simply 'break the circuit, so it doesn't matter where it is?
Put the switch wherever you want it. I would run the cable into the switch box (pattress is the technical term and you want a surface mounting one. If you go for a deeper one than normal then it is a doddle for you to carefully split open the cable by running a knife down the length of it and teasing out the three inner wires. Take care you don't slice into the insulation of any of them when you do this. Then you cut the live and connect that to your switch. The neutral remains untouched.
As you can see, I need some help!

Terry.
Click to expand...
 
Wizard9999":1pwrck93 said:
OK, now I have a proper thread for this, I'll push on further.

Power will be coming from the main house supply with a dedicated consumer unit (or whatever it is called) in the workshop. There will be a facility for isolating all the power in the workshop from inside the house just in case my children decide showing their friends how easy it is to remove fingers! I am planning 18 double power sockets (13A I guess) and three single 16A (or should it be more) sockets for tablesaw, possibly planerthicknesser (don't know yet as I haven't bought one so far) and a bit of future proofing. I plan to have six double flourescent lights in the ceiling as well.

As I have no experience of anything electrical and will have an electrician doing all the connections, etc. But want to do all the cable runs myself, as much as anything else so I can fit it around everything else I am doing on the workshop. I have a number of questions, which are no doubt basic to many others, but are far from it for me. Any help would be much appreciated.

1. How many of the 13A sockets can I reasonably run on a single 'ring', all of them or will I need to split it?

2. I assume the lighting circuit can be one separate circuit, correct?

3. Also the 16A sockets on a separate dedicated circuit I guess?

4. I understand 2.5m sq cable it typical for a ring main for 13A sockets, any suggestions on what should be used for the lighting and the 16A circuit?

5. does it matter where in the lighting circuit the switch is, does the cable have to go to the switch first, or does the switch simply 'break the circuit, so it doesn't matter where it is?

As you can see, I need some help!

Terry.
Click to expand...

All indoor cable 6242Y twin and earth.

All your 13amp sockets can go on a single 30amp ring with 2.5mm cable breaker should be B30

16amp sockets should be each be on their own radial - can use 1.5mm here but possible not worth buying specially - use 2.5mm? Breaker should be C16 for each radial.

Lighting Must be separate. Only need 1mm cable - breaker B6

Topology of the wiring run does not matter, but electrically the switch comes "first" in the circuit. Use a junction box (3 way + earth) to combine feed from CU, cable to switch and the feed out to the lights which would normally be daisy chained but can be series parallel with junction boxes if you like.
The cable to the switch needs a red sleeve on the black wire as both will be live when the switch is on

Don't forget earth to each fitting include switch back boxes even if they are plastic - its the rules!

Bob
 
Roger, Bob,

Many thanks for the quick and detailed replies, much appreciated. I will get an electrician to actually fit sockets, switches, etc., I would only probably mess it up and he would have to rework it before he could sign it off. All I want to do it run the cable around the workshop, probably in some form of trunking, as I don't think that is a skilled job, so perfect for me :lol: .

I'm building in a lot of spare sockets just to give me flexibility, so I suspect I will not have too many in action at once, but I'll have a good think about a 'worst case' scenario and then work out if I'll need two circuits.

Seems from a practical perspective that just using the same 2.5msq cable will be easiest, rather than buying small quantities of different ones, but will double check once I have decided on routes for cables and therefore lengths required.

When I run the cable around do I just leave some slck at the point where a socket, for example, will be, then the electrician can cut the cable and fix both ends into the socket?

Thanks again for the help,
Terry.
 
9fingers":w18gchn2 said:
Leave around 6" hanging out of each box (x2 for ring mains)

If you are daisy chaining your lights, then you might find the terminals wont accept two or three 2.5mm conductors. Best to stick with 1mm IMHO.

Bob
Click to expand...

Sorry Bob, what do you mean by "daisy chaining"? I know I'm an idiot, sorry.

Terry.
 
Think about a daisy chain - don't tell me you never made one as a child?

It means wiring one light after another in a chain and even teeing one off to the side under which condition, the terminals will have to accept 3 conductors.

Bob
 
....and dont mix cable sizes on the same run unless you have checked the screw terminals beforehand ! I made the mistake of using up some leftovers of 2.5mm2 cable while running the lighting circuits in 1.5mm2 in my workshop and then found that some types of terminals (budget fittings admittedly) wont hold the smaller wire properly if there is a larger one in the terminal at the same time.
 
Lets say you'd installed the lighting ring and then a month later you decided you wanted another strip light over a particular tool, task lighting style....a lathe say that wound up in a slightly dark corner somewhere. Can you take a spur off the main lighting ring? I'm thinking that this light would be a cul-de-sac.

So in this scenario firstly: a) can you do that and b) how would you do it? Would you need to cut the cable and stick a JB in and then run your spur light from there or could you just stick the new cable in the actual light fitting terminals (if there was room) and run that to your new light?
 
Firstly lights are not wired as a ring! They are one or more radials and yes the extra light can be added to the end of a radial or indeed tee'd off a nearest fitting.
There can be a problem when filament lamps blow as it causes a large current spike.
Something to think about but not mandated is to have one light that is normally on and yet does not go out when the breaker on the other ones trip. This means you are never(rarely) left in the dark with the possibility of running machinery.
It is not fool proof as the main breaker in the house could trip but then the machines would stop and all you have to do is stand still for 10 sec or so before moving. To be really posh it could be one of those battery backed luminaires but as they are factory H&S related, they can be expensive.

Bob
 
Rob":27d11gke said:
Lets say you'd installed the lighting ring and then a month later you decided you wanted another strip light over a particular tool, task lighting style....a lathe say that wound up in a slightly dark corner somewhere.
Click to expand...

No risk of that for me Rob as I won't have a lathe :lol: .

More seriously...

9Fingers":27d11gke said:
Firstly lights are not wired as a ring! They are one or more radials and yes the extra light can be added to the end of a radial or indeed tee'd off a nearest fitting.
There can be a problem when filament lamps blow as it causes a large current spike.
Something to think about but not mandated is to have one light that is normally on and yet does not go out when the breaker on the other ones trip. This means you are never(rarely) left in the dark with the possibility of running machinery.
It is not fool proof as the main breaker in the house could trip but then the machines would stop and all you have to do is stand still for 10 sec or so before moving. To be really posh it could be one of those battery backed luminaires but as they are factory H&S related, they can be expensive.

BobFirstly lights are not wired as a ring! They are one or more radials and yes the extra light can be added to the end of a radial or indeed tee'd off a nearest fitting.
There can be a problem when filament lamps blow as it causes a large current spike.
Something to think about but not mandated is to have one light that is normally on and yet does not go out when the breaker on the other ones trip. This means you are never(rarely) left in the dark with the possibility of running machinery.
It is not fool proof as the main breaker in the house could trip but then the machines would stop and all you have to do is stand still for 10 sec or so before moving. To be really posh it could be one of those battery backed luminaires but as they are factory H&S related, they can be expensive.

Bob
Click to expand...

So, if I understand correctly Bob, in an ideal world I should have two lighting circuits.

Circuit 1 (for safety) runs from the consumer unit to a junction box and then to the light, also coming off the junction box is the 'live loop' to the switch. This circuit ends at the light and does not return to the consumer unit.

Circuit 2 (main light circuit) runs from the consumer unit to a junction box and then to the first light, also coming off the junction box is the 'live loop' to the switch. This circuit the continues in a 'daisy chain' from the first light to the second, and so on. It ends at the last light and does not return to the consumer unit.

Is this correct?

Practically I would think the best thing is to put the safety circuit switch nearest the door with the main circuit switch deeper into the workshop, therefore making it necessary to always switch on the safety circuit, in case I end up getting lazy.

Regards,
Terry.
 
I appreciate you wont Terry (have a lathe)....I was trying to find out if that spur solution would work in my own garage without seeming to hijack the thread :)
 
Rob

I did guess that really, as you asked me to let you know before I ordered my lights because you wanted one more... memory of an elephant you see.

Terry.
 
I have 50mm square trunking running the full length of my workshop. The garage type consumer unit is tight up against the side of the trunking so wiring in/out is easy through a big cut out in the trunking. the armoured cable is power in from the house consumer unit. it is 4mm2 cable inside.
newstuff-152.jpg


Conduit drops from the trunking for metalclad sockets.
newstuff-153.jpg


My lights are enclosed GRP types and this one does have an emergency pack fitted.
newstuff-154.jpg


The sockets ring circuit does a lap of the workshop in plastic conduit as the large trunking is only on the one wall.
I'd recommend the large trunking as it made the wiring so much easier. I bought it online and it was quite reasonable. Something like £20 for 2 x 3m lengths I think.
 
Wizard9999":12x17ot2 said:
Rob

I did guess that really, as you asked me to let you know before I ordered my lights because you wanted one more... memory of an elephant you see.

Terry.
Click to expand...

Good point Terry and if you're willing I'd still like to do that in fact. If you tag 2 extra lights on to your order I'll cough for them as I want one over my workbench and one over my lathe. I don't care what you get, I know from the rigour with which you do your research that they'll be a good solution.
 
In my shop I have two dedicated lighting circuits, each with half my lights on it. I have to turn on two switches to get all my lights, but when I have to work on the lights I have enough from the other circuit to see what I'm doing.

Why bother with a ring main? Just put in a couple of branch circuits for the 13A outlets, or maybe one circuit per wall. Simpler to diagnose if something goes wrong.

Kirk
 
kirkpoore1":9fe1627y said:
In my shop I have two dedicated lighting circuits, each with half my lights on it. I have to turn on two switches to get all my lights, but when I have to work on the lights I have enough from the other circuit to see what I'm doing.

Why bother with a ring main? Just put in a couple of branch circuits for the 13A outlets, or maybe one circuit per wall. Simpler to diagnose if something goes wrong.

Kirk
Click to expand...
for standard 13amp outlets there is a maximum of 2 sockets allowed on a spur, otherwise it must be wired on a ring. Terry ought to be getting this signed off to what you would know as 'code'. UK has tightened up a lot in the last few years and wiring that has not been signed off makes it very difficult when it comes to insurance claims and selling. All the wiring colours have changed for the new regs and apart from some of us who hoard the old colour cables, new wiring is very obvious.

Bob
 
9fingers":1d9j9s1z said:
....... apart from some of us who hoard the old colour cables, new wiring is very obvious.

Bob
Click to expand...


Hoard cable? Moi? Actually the new colour coded cables were available about six months IIRC (certainly three) before the Part P date came into force. And there rests the case for the defence, m'lud.
 
I have a few lights that come on with the wall switch for general lighting but other lights over my various workstations that are controlled independently by pull cords or wireless control.
I can then give a good lighting standard wherever it's needed without having everything switched on.

Rod
 
9fingers":2qeigb8w said:
Kirk
Click to expand...
for standard 13amp outlets there is a maximum of 2 sockets allowed on a spur, otherwise it must be wired on a ring. Terry ought to be getting this signed off to what you would know as 'code'. UK has tightened up a lot in the last few years and wiring that has not been signed off makes it very difficult when it comes to insurance claims and selling. All the wiring colours have changed for the new regs and apart from some of us who hoard the old colour cables, new wiring is very obvious.

Bob[/quote]

Wow, that bites. I have, I think, four sets of four outlets on each of my 120v 20 amp circuits, and 4 240v outlets on each 240v 30 amp circuit. I mean, if you try to run too much stuff it simply trips the circuit breaker, so it's not like there's any danger. But code is code, you have to live with it.

Kirk
who will get more carving in tomorrow...
 
the trouble is of course that if someones house burns down due to an electrical fire and the wiring wasn't to code.....the insurance wont want to pay up!!
 
Well chaps, just to warn you, I will be coming back with more questions over the coming weeks. Electrician came back wit a quote for over £2,000 to wire up my workshop :eek:, so I will be 'insourcing' a lot of work and then looking to get it tested and signed off later.

Terry.
 
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