Wiring the Workshop....Garage!

My inquiry is:- Should I use top sockets like MK for around £12 a sho

or cheapies at £3.50 a shot? Metal clad of course. BTW, I don't wish to get into the 'should I do it myself bit/part argument' 'cos I AM doing it myself. Opinions much appreciated. Ro

-- elj221

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Nothing wrong with the "cheapie" sockets as such, I did mine with 8 double metal clad sockets and plastic conduit all around the garage/workshop and have not had any problems at all. Try Screwfix as they usually have good deals on for multiple amounts ;

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Reply to
Peter Fairbrother

I currently work for an electrical distributor, you would not believe the mark up on this stuff...

I'm talking 1000% or more

get yourself down to your local industrial estate in the am and follow the sparky vans to find your local distro

forget all ideas about "top" brands, that went years ago, the majority of it is imported, eg only one place in the uk now actually makes electrical cable...

metal clad sockets need a good earthing, cheapo plastic socket faces like contactum on appleby dry lining boxes is good enough, don;t scrimp on the cable gauge, make sure you install a loop and not spurs, and use a discrete breaker box with fuse and rcd trips for safety, so

10mm flat twin and earth from the house, and 2.5mm 3 core loop for the socket ring.

a box of ten fused rubber top lyvia 13a plugs is about 2.50 trade.....

HTH etc

Reply to
Guy Fawkes

The above statement tends to indicate that plastic boxes do not need the same level of earthing as metal. If that is what is meant then "cobblers"! The earthing is there for the item that is plugged in, not just for the socket.

In a workshop environment metal sockets are preferred. A long piece of bar falling against one will not cause the same level of problems. Dry lining boxes are for "Dry lined walls", the fact that the OP discussed metal sockets indicates that he is considering surface mounting, therefore "Dry lining boxes" do not come into the picture.

If you are using surface mount metal boxes then "Egatube" or similar is the correct way to go. A ring main in 2.5mm2 singles. Carry the earth around looping into each faceplate with a 1.5mm2 single wire back the the earth point in the box.


-- Richard

Nb "None" if the survey goes through ok

Reply to
Electricky Dicky

On or around Sat, 3 Nov 2007 12:55:59 -0500, elj221c enlightened us thusly:

The only thing I've noticed about really cheap ones is that sometimes the contacts within are poorly made, resulting in a poor contact onto the plug and generating heat. This obviously depends what you plug into it - light loads will never be a problem, 3HP motors might.

Reply to
Austin Shackles

I must admit that nearly all of mine were MK. But the only reason for that was that they came with the trunking that I scrounged from work to go with the other trunking that I got from Ebay. I like the 3 compartment trunking because it has plenty of room for future growth and also allows me to run the phone/network/loudspeaker/doorbell cables neatly.

Mark Rand RTFM

Reply to
Mark Rand

Nevertheless, a plastic socket fascia and box cannot go live, no matter what happens.

reaching out to switch on or off an appliance of necessity creates half the stance required for current to flow along your arms and across your heart and kill you, for the other half all you need is your other hand on something metalling with a potential difference, and 240 VAC @ 50 Hz is not required to kill, 6 to 200 milliamperes is all it takes.

Rubbish, in a workshop environment correctly sited, angled and protected lewden style plugs and sockets, armoured cables and so on are preferred, but this costs money and we are talking about a DIYer doing a "good enough" job on the cheap, not to code or to spec.

In that scenario, with the DIYer doing a "good enough" job on the cheap, plastic sockets are favourite, yes they can be broken, so can the metal ones, so take care, ideally put a shield around each socket in wood, top and sides, metal bars falling all over the place and liquid spills are signs of sloppy working practices.

dry lining boxes like appleby come in two flavors, cheap metal stampings and plastic, dry lining means any internal wall above a damp proof course, eg not a "wet" wall, like a single wall stone build structure with no cavity, their purpose is to recess the socket fascia nearly flush to the wall instead of protruding a couple of inches with surface mount, a lot of this depends on how you're going to run the cable, in the wall or externally in conduit, of course the OP is unlikely to spring for conduit too, so it will be cheapo and "good enough" thorsden style nail and piece of plastic cable ties.

won't happen, the tube is cheap enough, pence per metre, but the OP will prolly end up buying marshall tufflex round tees and elbows etc, and that's where the money starts to go.....

MT kit has again gone down hill in quality, we had a lot of pcv-u sterling stuff rejected, they're using a new cheaper grade of plastic and the rear (wall) side simply ain't flat anymore, but that's another story.

egatube etc also tricks you into all those extra little purchases, grommets and the like, that's where the money goes, and you have to be real careful, that stuff traps water, do it wrong and you can duct water down into a socket... seen it done....

why use singles instead of twin and earth?

6242Y has the same area, only one mousing / threading job to do per section, an extra free layer of insulation against electrical and mechanical issues, and it's cheaper, thanks to quantity of manufacture.

this is one of the *many* reasons old school sparkies and non sparkies have little time for 16th edition etc, 2.5mm2 has a nominal current capacity of 20 amperes, so in the UK about 4.8kW, with reasonable voltage drop, 1.5mm2 has a nominal current capacity of 15 amperes, so about 1200 watts less, you just put all your cookies in the earth wire acting as a sensor for the various protection devices MCB/RCD etc in the consumer unit to trip, and nothing left over for the old style of actually being able to carry any imaginable current thrown at it, without fuss.... so in the workshop enviornment this was every watt the live feed wire could supply, plus unforeseen stuff like the spindle motor failing and dumping excess phase current down it too

we don't even know if the OP has any potentially lethal kit in his workshop, like inverters to drive machinery or inside machinery such as welders, and wiring workshops professionally is a world away from wiring domestic premises professionally

so lets look again at what I said, bearing in mind we know he ain't a sparky working to code...

a/ 6242y twin and earth makes it easier to get right and harder to make mistakes*, plus its cheaper too.

b/ plastic sockets make it easier to get right and harder to make mistakes*, plus its cheaper too

etc etc

  • make mistakes means not just making them, but the after effects of them
Reply to
Guy Fawkes

should of course also have said that if cables are enclosed inside trunking then current carrying capacity is reduced significantly, no free air cooling etc....

Reply to
Guy Fawkes

More "cobblers". A dry lining box is used to fix a socket, switch etc into a "cavity wall"

I think that you are assuming too much about the OP's attitude to this job.

Again you are assuming the the OP is creating a workshop built in a swimming pool ;-)

Granted it's cheaper but why use the wrong kit for a job. If the OP decides to use tube then singles are the best way to do it.

I do not have a clue as to what you are on about! Re "acting as a sensor for the various protection devices MCB/RCD etc" Are you suggesting that the earth wire not be connected? I cannot understand your objection to 1.5mm2 for the earth wire, that is what is in your 6242Y cable and if I dismember correctly the old

7.029 cable had a reduced area earth well befor the 16th edition.! If you are unhappy with 1.5mm2 and suggest something larger, then singles are obviously the only way to go

If he has a 240v s/phase in and 415v three phase out invertor then I am sure you will recommend using 2 runs of 6242y and tying back the spare conductor. Look at the advantages you will say, two earth wires to act as a sensor ;-)

I leave it to the OP to do his own thing. One last point. If the OP wires in 6242Y it will be Brown/blue (After Part P.) If tubed in singles there is no identification as to when installed!

Reply to
Richard Edwards

not cobblers, fact.

the "dry" in dry lining refers to an internal wall above a DPC, eg a dry wall, as opposed to a wet wall.

don't be ridiculous, leaking roofs on outbuildings and garages are hardly uncommon, I've seen plenty of these leaks ending up as water dripping from a pendant light fitting or dripping out of a socket at the end of some conduit, hell, I've even seen plenty of example of water wicking down through coax from the external telly aerial....

it's not wrong, you're making assumptions, and quoting 16th ed, which isn't applicable to the DIYer, who is going to do a "good enough" job.....

twin and earth is cheaper than singles, tidier than singles, easier than singles and has that extra layer or electrical and mechanical protection than singles, it has everything going for it for the DIYer and nothing against it, 25 quid for 100 metres roll of 6242y and job's a good un

***FAR*** more important the OP is encouraged to flash the cash on a decent consumer unit and **appropriate** MCB/RCDs....

MCB come in three types for any given rated current, lets take a 16A one.

BMCB 16A will trip quickly at between 3 and 4.5 times rated current CMCB 16A will trip more slowly at between 5 and 10 times rated current DMCB 16A will trip more slowly still at between 10 and 20 times rated current

so, type D for thinks like transformers and welders, type C for inductive stuff like flourescents, and type B for everything else, CB = circuit breaker, a resettable fuse if you like, you still should fit and RCD to each circuit, this ( consumer unit) is where the money goes, twin and earth cable clipped to the wall with plastic contactum sockets etc is fine, esp if the money is spent on a decent CU with appropriate MCB/RCDs, that's where the safety will be made.

Reply to
Guy Fawkes

On or around Sun, 04 Nov 2007 03:55:22 -0800, Guy Fawkes enlightened us thusly:

get yer units straight. you can't mix volts and amps, you know.

Reply to
Austin Shackles

my units are right, UK mains is a nominal 240 VAC @ 50 Hz, 6 to 200 milliamperes is all it takes to stop the human heart, at 240 volts that's 1.44 to 48 watts, at 24 V that's 0.144 to 4.8 watts, a trivial amount of power, easily obtainable from a capacitor, whether you live or die depends upon the vagaries of the current path through the human body, if any and if so what proportion crosses the heart, if it's between 0.006 and 0.2 amperes you're dead, game over, end of story.

high frequency currents (like a tesla coil) in the kilo and megahertz range tend to run in the surface of the skin rather than through the body, very low frequency AC, eg 50/60Hz and DC are essentially the same, both run through the core of the body, the difference with DC is you have a 50/50 chance of the muscle spasm locking you onto the source of shock or making other muscles pull you further into the machinery, hence the "danger" of DC.

the illegal in the UK high voltage stun zapper things work off an internal PP9 battery, but use a fairly high frequency, hence pain but not death, unless you happen to have a pacemaker...


trivial things like selecting 6242y twin and earth over single gives you an extra layer of electrical and mechanical insulation, high voltage guys (tesla coilers etc) work with one hand in their pocket to prevent making a circuit across the heart, these are trivial things like correct use of the pusher stick on a circular saw, but they all increase the odds in your favour as/when/if the random event happens, by a significant margin, for approaching zero "cost" or effort.

Reply to
Guy Fawkes

Cobblers This is a dry lining box

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is a box for cutting into a solid wall
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Both are used in dry applications. Neither are required by the OP as he is intending fitting Surface mount metalclad sockets.

I will grant you all of these, however tube in a workshop is the way to go.

I have not quoted the 16th edition

How you can suggest that 6242Y has better protection than singles in tube I know not!

Thats a good price

I see a change of tack here away from some points raised

Better to take a 32A one as we were talking ring main for the sockets.

All of those breakers have similar tripping times at the suggested multiples of current. Needs a better description for the layman.

I look forward to your justification of this statement

Reply to
Richard Edwards

On or around Sun, 04 Nov 2007 08:32:16 -0800, Guy Fawkes enlightened us thusly:

not arguing that, but what you said sounded wrong, and I think was. Assuming correct figures, you can die from as little as 6mA across the heart itself.

The voltage is more or less irrelevant. You can and I have got many KV from vehicle ignition, but very little current. I've also had 240V mains, although not up one arm and down the other. Maybe I've been lucky.

Reply to
Austin Shackles

In article , Richard Edwards writes

Well, I'm no builder, but I had always understood that dry-lining was making internal walls with studding and plasterboard, i.e. "not using messy wet stuff like mortar or plaster". And of course plasterboard, having the structural strength of cardboard, needs different techniques for fixing things (including socket boxes) to it. Socket boxes (sorry if that's not the proper technical term) for plasterboard need to grip either side of the plasterboard rather than being screwed to it as with a brick wall.


Reply to
David Littlewood

Hey, steady on, am I missing something here? Is there something I should know about 'inverters' being lethal other than the plain obvious?? I'm just about to buy an inverter (1ph to 3ph) and 3ph motor very soon for my Myford ML7. I thought that inverters were simply to wire up. Surely, if all the mains wiring in the workshop is done properly, it shouldn't cause any problems. As long as the inverter is run from cables of the correct rating for the inverter, the mains and mains sockets are earth bonded and everthing fully insulated, what could happen? Given that I already run a mill via an inverter which is wired through a 'soft start' switch, isolating switch, fused mains switch, 2.5 T&E to a dedicated 10way consumer unit with 100A mains switch, RCD and adequately rated MCB, with full earth bonding directly to a new earth rod, I would have thought that things should be pretty safe ! I suppose what is being intimated at is the possiblity of touching something that is made live to 415v, well you wouldn't want to be subjected to 230v either would you? SOOooo, what do I have to look out for if inverters can be lethal? if everything is correctly rated, earthed and insulated??? I'm worried sick now. And I thought I knew what I was doing. Ah well, back to the kitchen sink (as long as it is earthed !!). Brad.

Reply to

usually just correct connection of functional earth / protective earth / pd equalisation, unless something happens to let the magic smoke out, internally they can use significant energies and voltages, which *should* be contained safely in a magic smoke escape event... should != always tho...

I'm sat looking at a bank of ten siemens caps, 350V 3300 uF, they look innocent enough too, I'm a *lot* more casual round them than my mate, who works with that sort of kit every day

Reply to
Guy Fawkes


Just do not grab two wires! 1 wire to ground is still 240v (or whatever your mains supply is these days)

I leave Mr Fawkes to put your mind at rest. Do not forget you need an additional RCD on that circuit! (according to Mr Fawkes) BTW which invertor are you purchasing?

Reply to
Richard Edwards

Not 100% sure about this but I have a feeling the RCD on the incoming side won't protect you from accidents on the output of the inverter.

You won't regret it :-)

Reply to
Duncan Munro

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