How many sockets?

[PJW]

I have almost finished building my new workshop and installed a ring main with 16 sockets on. The majority of these are now in use, the lathe, miller, grinder, spot light, Phone extension, pillar drill and 2 battery chargers spring to mind. How many is enough & if I am using them all will the lights in the house dim!!

[spuddevans]

I have a total of 11 double sockets in my recently built workshop, and while they are not all in use yet, I'm pretty sure that I will be plugging in a couple of 4-gang extension sockets when needed.

I guess how many you will need will probably turn out to be double what you think you need 


Tim

[b.lindsey]

That could be a lot if all on one circuit but its unlikely that you will be running everything at once. If you start blowing the circuit breaker though you will know its too much!!

Bill

[Jo]

The real question is what size is the circuit? The Prazimat will take a fair few amps, in the winter you will have a 13 Amp heater, some lights on.. You will be getting close to 30Amps.

I have three ring mains in my workshop: A 30 Amp circuit for the standard sockets, a second 30A for the night storage heaters and the 45 amp circuit for the three phase machine tools. The lighting is on a separate fuse box (15A ring) so that if the equipment trips the box I don't get plunged into total darkness 

Jo

[Don1966]

Like Jo said, it depends on what size circuit, the distance from the circuit and what size wire you used. Most of American standard receptacles are 15 amp rated. Having a string of them does not mean we load each down with 15 amps of current as that would not work, because the breaker would trip. Check the current draw of all your equipment and total it. Remember that motors will draw three times there max current on startup so if you are close to the breaker current it may cause problems.

Be warned do not size the breaker for more then the current rating of the wire and if you have distance from the source you will have voltage drop and will notice lights dim when heavy equipment is turned on.
Hope this helps.
My I suggest that you designate heavy current equipment to there own receptacles.

Don

[PJW]

I think Tim is right, think of a number & double it, as as for you Jo you dont have a workshop you have a factory, just short of staff.
yes Jo I do have green eyes!

[Alan Haisley]

Look out for equipment like compressors and vacuums that you likely will run along with other machines. Machines that will run at the same time may need their own runs. If the space is big enough you may want two light circuits so that if one goes you can still see.
If someday you will have an annealing oven you might provide separate power for it up front.
Benches for electronics, soldering, and hand power tools can never have too many outlets.
Alan

[sshire]

When I originally did the shop, my electrician, a hobby woodworker, insisted on a 100A subpanel. He said even though it seemed like a lot, I'd be glad he did it. Absolutely! I have 15 double boxes, the lathe, bandsaw and compressor are on their own breakers. The 240v for the Bridgeport on double breakers.
Lighting on two circuits. My point is, if you can, spread the loads. You can never have too many circuits.
Realistically, the mill and lathe are never running at the same time. The compressor kicks on when it feels like it.

[Stuart]

this is a question that supports my reason for the OP of a electrical question to state their country as UK and US systems differ considerably

I would assume the OP is in the UK when he refers to a ring main ,but I am not sure


in fact for a workshop in the UK I would do as Jo has done multiple ring mains but wire them in 4mm twin and earth with a 32 amp mcb for large use ( heavy start up loads ) I would install a radial system in 7mm with a 45 amp mcb

Stuart

Time served sparks when you did a five year apprenticeship

[PJW]

Thank you all for you helpful comments, many of which will be acted on, some are already in place,

Peter