Garage / workshop electrics

[John Rumm]

Non RCD side makes it easier, since you can then use a split load CU in the workshop/

Regards capacity - the short answer is yes you probably can upsize the MCB, however there is stuff to check first.

As to MCB brands etc, its easiest to get the same type if you can. However there is some level of interchangeability. See the early draft of the interchangeability table here:

your SWA:

How many cores?

According to my table here:

core 4mm^2 is 14.7mm diameter, and 3 core is 15.3mm diameter. So that seems possible.

The smallest 6mm^2 is 15.9, and the largest 2.5 (4 core) is 15mm - so probably not those.

So 4mm^2 seems possible...

How long is the cable run in total?

Does the SWA go right up to the house CU or does it switch to T&E first?

What earthing system does you house have?

3. This is strictly for hobby use, lathe and milling machine use less

Yup, a dedicated circuit with a type C MCB may be required for that.

Which means you can forgo RCD protection on the lighting circuits then if you wish. (or use a RCBO anyway)

Again, it partly comes back to what earthing system you have. If you have a split load CU with only one RCD then it must be TN-C-S or TN-S. The former can normally be spotted by the way the main earth connection will come from the cable head end unit adjacent to the neutral tail. (TN-S will usually be a connection to the cable armour before the termination to tails). Post a photo somewhere we can see it if in doubt.

Any other services into the garrage like mains water, gas etc?

[Harry Bloomfield]

JimM brought next idea :

I would suggest having at least two socket circuits, such that you can have sockets which remain live all the time (for battery chargers, garage door etc.) and another for sockets which need to be isolated as you walk out the door, such as your machine tools soldering irons etc..

Rather than light switches, I use separate MCB circuits to power lighting in different areas. I also have one light on a PIR, so it comes on when ever I enter the door or drive the car in or out.

It might also be worth including an emergency ALL STOP system in the circuit used for the machine tools.

[robgraham]

Jim - you really must re-consider the door situation. Up and Over doors are a major problem and hazard for workshop situations. I'll come to the hazard in a moment but if you are wanting to work for any extended period in the winter months this type of door just keeps nothing at bay - water, dirt, cold and wind leaks are quite unimportant to a car, but are all a total disaster to a workshop.

Now to the Hazard - have one door and you have only one escape route in case of an accident; have an Up and Over and that escape route becomes even more dangerous as, whether manual or electric (and what happens if the electric fails), they are slow and difficult to operate from the inside. I speak from sad experience - my father died because of a problem in his workshop and he couldn't get out fast enough - only one exit and it was an Up and Over!!

Rob

[deano]

I think that says it all. You need to be prepared for the worst case scenario, whilst you are in the workshop. Could you operate an up and over door in the event of personal injury.

Sorry to hear your story Rob, it must be painful to read this thread.

Dean.

[robgraham]

Thanks Dean - I appreciate that. Fortunately now it was 20 years ago and long enough that I can use it as a warning to others without any upset.

It does concern me slightly however that with so many respondents to the original posting, that on-one else has picked up on my point. I do suspect that there are a lot of garage workshop users burying their proverbial heads and saying 'it won't happen to me' !!

Rob

[John Rumm]

If its any comfort, I fully agree. However since you had already mentioned it, it did not seem worth repeating, especially given the weight added with the recounting of your personal experience.

Probably true - or equally likely they have never thought about it.

(I suppose the actual risk varies quite dramatically with what one actually does in a workshop).

[deano]

It does make you wonder. Also gives some credence to the, often criticised, attitude of the HSE these days, as being over-exuberant. Time for another national statistic - this time regarding the amount of workshop injuries that occur across the UK each year??

I do know that A&E admissions spike at Easter time (especially concerning 'falls from ladders') so, in 2 weeks time... it's 'Open Season' on all Destroy-It-Yourself'ers ;)

Be warned Group Members.

[JimM]

Hi Rob

Sorry to hear of your experience but thanks for the input and the warning has been heeded. Unfortunately there's no way I can put another door into the garage. My house is on a steep slope and only the front wall of the garage is at ground level, with the other 3 sides effectively 'in the air' (There is a window but with a 12' drop from it)

I do take what precautions I can and have a couple of fire extinguishers on hand but I will also do a dummy 'emergency evacuation' just to make sure I 'm comfortable on how to open the door in case of power failure etc

Thanks

Jim

[dennis]

The obvious thing is to never close the door while anyone is inside.

[js.b1]

What is stopping you doing the following?... #1 - Replace the up-&-over door with one that has a "safety doorway" in it. #2 - Replace the up-&-over door with conventional double opening doors, with a "doorway" in them if necessary, with cranked hinges if necessary.