Bigger than a ring main ?

digger · 24 Nov 2004

A have purchased some 240v woodworking machines and in total, if all were running a the same time, very unlikely, they would produce about 7kW. More than normal a 4-5kW would be more normal. Some machines are 3hp (about 2.25kW) and seems to be on the limit of a 13amp fuse. A have spare spaces in my consumer unit and was wondering the best way to \\\'wire up\\\'

I will eventually obtain a qualified electrican to carry out the work but was interested in the solution first.

Many thanks

Richard

andy · 24 Nov 2004

what premises are you in? do you have a single or 3 phase supply? how many machines do you have and are they in a permanent location or will they be moved?

onion_soup · 24 Nov 2004

andrew2022 said:
what premises are you in? do you have a single or 3 phase supply? how many machines do you have and are they in a permanent location or will they be moved?

how do these differ a single or 3 phase supply ? I am thick keep it simple

ban-all-sheds · 25 Nov 2004

3-phase is 3 single phases, 120º apart.

http://en.wikipedia.org/wiki/Alternating-current_electric_power

http://en.wikipedia.org/wiki/Single_phase_electric_power

http://en.wikipedia.org/wiki/Three-phase_electric_power

digger · 25 Nov 2004

6 machnies all single phase. No 3 phase available, will all be permanent in a plain breeze block wall. no plastering, similar to a garage.

Thanks

andy · 25 Nov 2004

few options of how it can be done. 10mm cable from CU thru 50A breaker into garage. isolator there. then thru trunkin to an isolator nxt to each machine - machine hard wired into isolator (by isolator i mean the metal ones with a large handle). or in industrial socket next to each machine.

mains CU-- 10MM cable -- garage isolator -- 10mm cable-- isolator machine 1 -- 10mm cable -- isolator machine 2 etc.

other way is to have the same as above to garage, small CU, main isolator and 6 16A MCB's, each feeding 1 industrial socket nxt to each machine

digger · 26 Nov 2004

Thanks for your help.

Regards

Richard

brown-nought · 26 Nov 2004

A lot depends on what you are doing with the machines. If you are talking about a few wood working machines that all have standard (BS1363) plugs on them and are intended for home/DIY/amateur use then that’s very different from commercial/professional use. In the pro case you need to consider Health and Safely legislation.

If it’s for home use with standard sockets then a 32A 4mm Radial circuit may well be sufficient. As you said normally you would normally only draw 5Kw (22A@230v) even 7Kw is only 31A@230v.

I’d protect it behind a 30ma RCD and provide a method of isolating the entire radial from the workshop. Plug each appliance into separate socket (i.e. use only 1 gang of a 2 gang socket). You could use metal clad surface sockets, round 20mm conduit with singles. (That way it will be easier to upgrade in the future if needed.)

If your kit is more industrial then things will get more complex (and expensive) – especially when starter circuits, power factors and NVR/emergency stop switching is needed.

MattBeard · 26 Nov 2004

Better yet in this case I would install single sockets... otherwise one-day you, or someone else, will forget and plug the two biggest machines into the same double socket.

A double socket is not designed to supply 26A!!

Odd one that and many people forget it!

dw3101 · 27 Nov 2004

Personally I would hardwire each to an Isolator or use the industrial style 16a or 32a sockets with an isolator at each. (not sure if this is a requirement?)

David

Adam_151 · 24 Feb 2011

I reckon that after 6 years hase passed that he will have sorted it

MrTinker · 24 Feb 2011

Adam_151 said:
I reckon that after 6 years hase passed that he will have sorted it

Well yes he probably has, but why the need to mention it

Lectrician · 25 Feb 2011

Yea Adam, can't work ou why your bothered, lol.

securespark · 25 Feb 2011

StelleElectrical · 25 Feb 2011

lol a 6 year old thread brought back to life haha

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Bigger than a ring main ?

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