Electrics upgrade

[Deadeye]

My "workshop" is a double garage that I've gradually taken over (movers out, tools and benches in).
The current power supply is 13A from the main board (buried; armoured) and supported a single double socket and four strip lights.
I've ended up adding more lights to that loop and then a big rack of extension sockets that then run to the machines.
It's evolved over time, and is neither pretty nor likely to pass a building inspection.
So I need to bite ht ebullet and get a professional to make me an honest man.
Questions:
- what level of suppy should I seek from the main board? 32A?
- any specific considerations? I want to be flexible as I'm still moving things around and not convinced the tools are in the best final places (and I'd like some on wheels to move around as needed)
- how much pocket money do I need to save up? Broadly. To the nearest hundred? To the nearest thousand?
Any advice welcomed

 

[sunnybob]

Youve missed out the important detail, what size wires are in the buried armoured cable?, and how many wires?
That will tell you how many new toys you can buy.

If you switch to LED lights that will save you a bit of power as well.

 

[kevinlightfoot]

I was in a similar situation ,I installed new armoured 10 mm cable from the supply to a new submain and then a new ring main for the sockets and three 20 amp radial circuits for my machines.I also put in new lighting,I used fluorescent tubes but now wish I had used l.e.d.s.Ask your electrician about the main fuse.I didmost of the work myself them my electrician checked it and coupled up the power.Total cost was probably around £500 including the electricians fee,hope this helps regards and Merry Christmas Kevin.

 

[sunnybob]

If you have to install a new power line to the workshop, you might hit a grand depending how much cable you need (armoured aint cheap :shock: ) If your cable is big enough, then youre only into very low hundreds for all materials and lights.

Its very important nowadays to get this kind of work signed off, and to KEEP all the paperwork! When you come to sell, you will have to prove its all to spec or take it all down before the sale goes through.
Lucky you lot with your limitless power. My main board is 40 amp, and there are 5 A/C units in there as well as the house and the workshop. :roll: :roll:

 

[Sideways]

Think of the work you do and add up the power of the worst combination of tools you are ever going to use at once:
Big router : 2.2kW or large tablesaw 3kW or planer 2 or 3kW ...
Dust extractor : 1.5kW
Electric heater in winter : 3kW
Lights : not much
Air filter : only 0.1kW so trivial
Compressor if you have it on in the background : 1 or 2kW
Add them up : about 7kW if you DON'T run a compressor full time or in winter.
Crudely 4.5Amps per kW
And round up to the nearest standard circuit breaker rating so you're probably looking at 32 Amps.
Be a little bit careful as induction motors will pull maybe 5 times rated current just for a second or two while starting. Check the manufacturers advice on what size wiring and breaker to use if you have any big machinery and don't start multiple high power devices at the same time.
You can have as much gear as you want, what matters is how much you have running at the same time. That gets much worse if you ever have someone else sharing your space.

 

[stuartpaul]

I was also in the double garage conversion situation but the original supply was bog standard 2.5 mm cable and no way would it take the sort of loads I was looking to impose.

Changed to 10 mm armoured with a sub board from the main board. I was having a lot of other work done at the same time but it didn't add a massive amount to the overall bill (total bill was less than a grand so hundreds not thousands, - 2 years ago). I did all the internal wiring (LED lights) and had it signed by my sparks.

Had to have a couple of the breakers changed for 'slower' ones as start up current can cause tripping.

As Bob says get it all signed off and keep the paperwork!

 

[Deadeye]

Youve missed out the important detail, what size wires are in the buried armoured cable?, and how many wires?
That will tell you how many new toys you can buy.

If you switch to LED lights that will save you a bit of power as well.

I'm not sure! I guess I could tell fromthe breaker on the main board?
All the additional lights are LED... but these days I seem to need it to be like an operatingtheatre before I can see properly!

 

[Myfordman]

Look at the fuse where the power enters the property before the meter. Typical uk will be 60A for older set ups and 100A for modern.
Quite often the leccy board can increase a 60A to 100A provided the incoming cable is rated for it.

Cable size depends on length and load look on TLC website for a useful calculator.

When you get it installed make sure the house end has a C type breaker fitted. these are more tolerance to high peak loads when motors start up.

Insulate and draughtproof your workspace. It will cut your heating needs enormously and that might just save you a cable size step too.
My workshop is 30 sqm and 750 watt oil filled radiator on a thermostat is all I need to keep it comfortable.

If you are cunning you can arrange for a compressor not to start up when a large load like a table saw is running. Again might save you a cable size or even let you use your existing cable. Design to what you can get away with not an ideal world and you will save £s without compromising safety.
Most sparks will do the opposite!

 

[sunnybob]

Youve missed out the important detail, what size wires are in the buried armoured cable?, and how many wires?
That will tell you how many new toys you can buy.

If you switch to LED lights that will save you a bit of power as well.

I'm not sure! I guess I could tell fromthe breaker on the main board?
All the additional lights are LED... but these days I seem to need it to be like an operatingtheatre before I can see properly!

If you want to stay alive, trust no one. :shock:
There are many, many cowboys adding bits and pieces to electrical systems. Fuse size DOES NOT guarantee cable size (I've seen 4 mm cable forced into a 13 amp plug, and 1.5 mm cable running loads that should have 4 mm to work safely).

Get a sparky that has a good reputation to come and find out what you have. Tell him you will do all the hard graft and let him come back and inspect.
Bite the bullet and pay.
If you have any kind of bodge on the wiring, and the very worst case scenario happened and your place caught fire even if it wasnt on your extension wiring, without proper paperwork your insurance company would laugh in your face.

 

[user22161]

I'm surprised at some of the replies for what is a pretty simple job. Obviously the first job is to see what size of cable is installed and whether it needs upgrading. Several on-line tables for cable sizing, a couple of results here - 2.5mm armoured single phase will take 36 amps with voltage drop of 19mv/amp/metre whereas 6mm will carry 62 amps with voltage drop of 7.9mv/amp/metre. Not all machinery will be operating at the same time so a bit pointless adding it all together to arrive at load.

I laid a new 6mm armoured cable from consumer unit to garage (around 18m) plus 2 new rings and some spurs, a small consumer unit, rcd, mcbs etc and the cost of materials was under £200. A mate who is an electrician changed the old main house consumer unit, did a wiring test of old and new and charged £120.

Cable table here, see P8 for armoured - http://www.aeicables.co.uk/literature/C ... atings.pdf

 

[Wallaceandsons]

I was charged 940 for a new fuse box, 5 new double outlets, moving the 16 amp plug, 2 new led strip lights and a fan. Felt pretty ripped off tbh and they broke my alarm.