advice / help needed on garage electrics

[bunnymofo]

hello, i am getting a new garage built and am not sure what size of cable or breaker to use to supply it, it will have just single phase. a 2 post lift which needs 32A, welders, 32 amps each, compressor, now sure how many amps yet. obviously they wont all be getting used at the same time, but the compressor and the lift could be at the same time. and obviously will have lights and sterio and all that too i will have domestic 13A sockets, 16A sockets and a coupple of 32A sockets, also 110V sockets. any advice ?

[Allvaux]

I reckon you're going to need 3 phase to handle that sort of kit.

[bunnymofo]

i would go for 3phase, but itl be enpensive i was thinking either 10mm or 16mm T&E cable ?

[bunnymofo]

??????

[jamied]

i have just kitted my my garage out but no ramps used a 100amp RCD fuse box with 1x16amp for lights, 1x32 for sockets, 1x32 for welder, 1x32 for extra storage shed built on.
as said you will not be using all at once so no risk of over load.

From the house fuse box i used power shower wire to the garage fuse box.

Will do for little jobs and what i need as the main garage has all the other kit.

[Dom]

I've got a 15 amp supply going to mine ..

In the winter if I need to print something I have to turn off the heater so the laser printer won't push it over the edge lmao

[show n shine]

^^lmao

[bunnymofo]

ahh, so 60 amp should be ok then ?
with shower / cooker cabble to it.
lool at the turning off the heater to print, thats like my currant workshop, 16A supply, and runs 2 large freezers so therenot much left for anything aha

[Dom]

Don't forget your gauge of cable is also dependent on the distance you are running it.

For example, a 32 amp cable may be fine for a 10 meter run but on a 30 meter run you'll find you drop far too many volts under load so it will need to be upgraded to a higher rating even if you're not using that amount of current.

[bunnymofo]

ahh, i willneed to mesure how far it will be, but my mains voltage it anywhere from 267 to 284 v AC. so would some drop be ok ?

[Dom]

"some" drop is unavoidable - its how much of a drop your equipment can tolerate that is more important.

Another thing people forget is the wasted cost of energy. Say you are taking 40 amps with a drop of 40 volts (thats only 1 ohm cable resistance so 0.5 ohms on neutral and 0.5 ohms on live). That 40 volts at 40 amps equates to 1600 watts of energy (Power=Current x Voltage) thats being wasted to heat up your cable / garden ...........

[bunnymofo]

so basicly the thicker the cable the better ?

[Dom]

Yup - you can't go wrong with seriously thick cable

[bunnymofo]

lmao so 16mm T&E then ?

[Dom]

lmao - if you can afford it.

In fact go all the way and get meter tails lmao

[bunnymofo]

lol, well thats the problem,.i cant afford it lmao

[king nero]

Measure the length of the cable, and do tell what power supply (in Amps, and single of 3 phase?) you have where you will be taking the current from.

If you have 63A available in your garage, you'll probably be fine?
16 sq mm possibly won't be enough, depending on the length of the cable.

I don't know the regulations in the UK, but you'll want a 30 - 300 mA "leaking/differential current" breaker (dunno what it's called?) as well for your own safety, and a separate grounding installation for your garage might be wise for anything over 20A.

[bunnymofo]

i will mesure it today, if i can find a tape messure. i will be taking the power from the consumer unit in my house. single phase. if bigger than 16mm, then what shat size ?

[Dom]

You can buy me a beer if we ever meet lmao

Cable Size Selector Calculator and online cable selector for electricians

[king nero]

If you're taking the power from your house, do you have more than 63 Amps available? Please do check this first!
No point in buying 16 sq mm cable if your house only has 25 amps main breakers...

and could someone else (from your country) please elaborate on this as it's fairly important!

I don't know the regulations in the UK, but you'll want a 30 - 300 mA "leaking/differential current" breaker (dunno what it's called?) as well for your own safety, and a separate grounding installation for your garage might be wise for anything over 20A.

especially the first part! (assuming you've got an TN-S powergrid)

[bunnymofo]

assuming you've got an TN-S powergrid

Whats a TN-S powergrid ?

[bunnymofo]

You can buy me a beer if we ever meet lmao

Cable Size Selector Calculator and online cable selector for electricians

i can do better than that, il buy u a box lmao

[bunnymofo]

You can buy me a beer if we ever meet lmao

Cable Size Selector Calculator and online cable selector for electricians

it says i can use 10mm T&E for up to 12KW at 230 V over 30 meters buuut, my voltage is anywhere between 267 and 284, so would the same rules apply ?

[Dom]

How are you measuring it ? Peak to peak or RMS ?

A 230v RMS supply will give you around 320v peak to peak

A "theoretical" single device (i.e. a theoretical heater) that draws 12kw at 230v will take around 52 amps. If however you plug this into a 284v RMS supply then it will take up to 14.8kw.

Plugging this value in to the cable calculator comes up with 16mm2 cable so I'd go that way to be on the safe side and limit the maximum total value of your appliances to 12kw (when rated at 230v).

[Dom]

P.s. had a couple of beers so E&EO excepted lmao. Should be reasonably accurate though