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.
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View this thread: http://www.rcgroups.com/forums/showthread.php?tv673
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 ;
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
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
a box of ten fused rubber top lyvia 13a plugs is about 2.50 trade.....
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.
Nb "None" if the survey goes through ok
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
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
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
* make mistakes means not just making them, but the after effects of
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
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
If tubed in singles there is no identification as to when installed!
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"
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
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
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.
This is a dry lining box
This is a box for cutting into a solid wall
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
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
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.
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.
On or around Sun, 04 Nov 2007 08:32:16 -0800, Guy Fawkes
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.
Austin Shackles. www.ddol-las.net my opinions are just that
Travel The Galaxy! Meet Fascinating Life Forms...
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 !!).
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
Hi, I'm not sure at the moment regarding a particular inverter for the ML7
but I live very close to Drives Direct, who also have a damned good web
site. The current motor (1ph) is the original Crompton/Parkinson 3/4 hp
motor, Drives Direct do a 'package' of a 3/4 hp phase inverter and 3 phase
motor for £150. This is about the limit of how far the pennies will stretch
at present. I thought about a remote stop/start/forward/reverse switching
and a digital tachometer (as discussed in another thread on this forum) for
determining actual RPM. The main thing, other than ultimate speed control,
is that I would like to rid the lathe of the eternal "thump" when switching
on the motor as it is at the moment. I thought that the MEM soft start
switch was supposed to help in that respect !!
The thing I'm not sure of with respect to the inverter package is whether I
would need a mains filter to go with it.
Ideally, I should be thinking of building an inverter from scratch as I
have a good electronics background, but it may be easier to just buy the
inverter ready to run.
Any thoughts on any of the above would be most welcome.
Now I AM worried !
I can probably see where you are coming from regarding the RCD may not
provide protection on the output of the inverter.
I will have to try and check this point out a.s.a.p.
Has anyone got an answer to that one?
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