Electrics for the Workshop

[wizer]

Hello

I had an electrician round tonight to spec up for a quote to install the first fix electrics in my workshop. He is running a separate circuit box straight from the metre into the garage and taking off 3 spurs: sockets, lights and external lighting. I have asked him to run 18 double sockets and 4 strip lights. It was a bit spur of the moment so that's all I could think of. Is there anything else I need to make sure he is doing? I am going to do second fix which shouldn't be a problem, he is happy to sign it off for Part P.

Cheers.

 

[Lord Nibbo]

A couple of 16amp supplies should you need it.

 

[wizer]

sorry for my ignorance, but where would I need 16amp?

 

[Waka]

sorry for my ignorance, but where would I need 16amp?

Just in case you secum to some big powerful machines.

 

[neilc]

What I find useful in my workshop is a master off switch for all the sockets. All he has to do is run the socket circuits through a contactor controlled by a key switch. Puts my mind at rest should one of my young ones get in there when I'm not around. I also put in three extra stop/start stations around the walls for my dust extractor.
Hope this helps.
Neil

 

[davy_owen_88]

If I can offer one bit of advice it would be that when choosing the feed cable be sure to let the electrician know a sensible figure for maximum demand i.e chose the most power hungry tool you have and then consider every light on plus the extractor, radio, kettle and then add a bit for good measure so that he can chose a cable that is suitable. Getting this right is vital unless you want to rip it out and start over again the next time you buy a slightly more powerful tool/extractor etc.

Installing one size up on the calculated cable size is always a good idea if you can see yourself upgrading your tools in the near future, not only does it give you room for upgrades but it reduces the voltage drop which can become an issue with motors due to their high starting currents, starting an extractor and a tablesaw at once may see close to 100A of inrush current for up to a few seconds, this is not enough to trip the MCB but it can cause unacceptably high levels of VD which can mean the machines fail to start.

Oh, and don't install one of those 'garage consumer units' with only 4 ways. You'll want a 6 way CU at least if you think you'll want some 16A outlets.

Davy

 

[wizer]

lovely thanks guys. I think he did mention a garage consumer unit, so I'll make sure it's at least a 6 way.

Not sure if i'll ever need 16amp but no harm in putting one socket in just in case.

Not far off completion now (hah!) Just got to insulate, board and 'tart up' the front and back.

 

[j]

As suggested a master kill switch is a great idea. Something I wish I had.

And if you do this, it might be worth getting a few extra sockets not covered by the kill switch for all those chargers for cordless tools etc.

And while I think about it, depending on the size of your shop and the tools you have, you might want some sockets in the middle of the room either on the ceiling or under a floor box or something.

HTH
J

 

[ByronBlack]

I have a master-kill switch from my installation and it's a real boon. I would also recommend maybe having a couple of spur sockets for use for seperate security lights or an external extractor if you ever go down that route.

Glad your getting further down the line with the build wizer, any updated photo's?

 

[Chris Knight]

Tom,
My table saw and compressor both need 16 amp. The saw draws a huge amount at startup ( I suppose the compressor does too but an electrician measured the saw, it's around 30 amps or so) which drops rapidly to a much lower level but without that 16 amp circuit and some sort of slow-to-react breaker that was installed for it , it is guaranteed to trip the supply.

 

[andys wood shed]

WiZer

Another suggestion might be for a fused spur conveniently located for an alarm

Regards

Andy

 

[wizer]

right so, this is getting confusing

I need the following circuits

Lights
Sockets x 10 Doubles
16amp Sockets x 2 Doubles
Security and External lights
Alarm

So that's a 5 way CU. Does the kill switch come with the CU? Could I not just flip the circuits off that I don't need when not in the WS?

At the moment I have the RSDE2 dust extractor, triton ts, router and the mitre box. I have never tripped the RCD in the house so far, I realise if I get anything beefier it may well. So how do I work out the cable size?

Not really any photos atm. I am doing bits and pieces when I can. My Dad is a caterer and seems to be much busier over the winter period, which has meant I haven't had any help on the heavy or awkward jobs. It probably looks terrible at the moment as I am doing jobs all over the place and not being able to complete them til I get help. Another couple of months and we should be there. :roll:

 

[Nigel]

One other thing I would not be without now is some form of emergency lighting in the workshop
If you are using a machine when there is a power cut its good to be able to see any rotating parts even if they are slowing down
There are some light units that combine the lighting if you are buying them yourself although not cheap

Nigel

 

[ByronBlack]

right so, this is getting confusing

I need the following circuits

Lights
Sockets x 10 Doubles
16amp Sockets x 2 Doubles
Security and External lights
Alarm

So that's a 5 way CU. Does the kill switch come with the CU? Could I not just flip the circuits off that I don't need when not in the WS?

At the moment I have the RSDE2 dust extractor, triton ts, router and the mitre box. I have never tripped the RCD in the house so far, I realise if I get anything beefier it may well. So how do I work out the cable size?

Not really any photos atm. I am doing bits and pieces when I can. My Dad is a caterer and seems to be much busier over the winter period, which has meant I haven't had any help on the heavy or awkward jobs. It probably looks terrible at the moment as I am doing jobs all over the place and not being able to complete them til I get help. Another couple of months and we should be there. :roll:

Wizer, if you need a hand with any of the heavier/awkward jobs, I would be happy to come over and lend my services.

 

[engineer one]

certainly think it is sensible to think about a couple of roof mounted sockets, and then one of those brunnenstahl hanging cubes. cuts down on the amount and number of cables on the floor.

a couple of kill switches if you are working alone much of the time.
one near the biggest and most dangerous machine, and one near the door which you can shut down as you go out, to be sure. certainly a good idea these days to think about stopping any current going into the garage overnight. if we are told to turn off tv etc on standby, then it makes sense to think about same in workshop i guess. :roll:

paul :wink:

 

[Nigel]

Wizer
you posted the last as I was typing
Your electrician will probably run the 13amp sockets in a ring this is the circuit to put on a contactor for the kill switch

You will need a 24/7 supply for an alarm and poss charging station

I would suggest you only make provision for any 16amp supplies at the CU as these will be dedicated to specific machines and can be run in when and if you buy any

Nigel

 

[wizer]

Byron: thanks mate, that's very kind. i have the old man booked for sunday the 11th. If we don't complete the heavy stuff (the doors) then i'll be calling! Once the doors are on I have a whole load of little jobs that I can be getting on with which should keep me busy.


Ok, next silly question. Why not just make all the sockets 16amp? I clearly know nothing of electrics

 

[Nigel]

Wizer wrote
Why not just make all the sockets 16amp?

Because you would have to change every tailed tool you own to a 16amp plug and you would not be able to use them anywhere else except your workshop and the cost and cabling would be prohibitive

There are very few machines you are likely to buy that require a 16amp supply so worry about that when the time comes provided you have the facility in the CU no big problem

Nigel

 

[wizer]

fabby. all clear, thanks.

 

[davy_owen_88]

I need the following circuits

Lights
Sockets x 10 Doubles
16amp Sockets x 2 Doubles
Security and External lights
Alarm

So that's a 5 way CU. Does the kill switch come with the CU? Could I not just flip the circuits off that I don't need when not in the WS?

You need 2 ways for the RCD, 1x 32A MCB for the ring main, atleast 1x 16A MCB for the 16A supply, 1x 6A MCB for the all lights, (internal and external) and a suitable MCB for the security (3A is probably fine but depends). So go for a 6 way CU to give 1 way spare for future expansion.

You don't wire double sockets for 16A supplies as they are not made to sustain a current of over 13A for a long period of time - you use these.

The MCB's in the consumer unit are not designed for frequent switching, and should not be used as the master kill switch, use something like this.

At the moment I have the RSDE2 dust extractor, triton ts, router and the mitre box. I have never tripped the RCD in the house so far, I realise if I get anything beefier it may well. So how do I work out the cable size?

The RCD will not trip due to overload as it only detects earth leakage, I think your thinking of MCB's

To work out cable size I'll need to know the total distance from your house CU to the CU in the workshop and the expected maximum demand (I explained how to determine this in my last post).

Davy