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Garage Electrics tech


Astro_Al

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Righto Guys, I'm not satisfied with the electrics in my garage. Running my welder on full blast, amongst other things, blows the trip switch (locked away in another building, dammit). It gets pretty dangerous being plunged into darkness in the middle of an 'operation' sometimes, and I need full power for my cage welding. Plus I've been acquiring tools at an alarming rate, most of which cannot be run simultaneously (like the air comp switching itself on while I'm using a different tool and blowing the circuit). So I need to fix it. I also need more lights too (= more power).

I guess the best thing is to keep the circuit I've got and use it just for lights and low power stuff - grinder etc, and rig up a completely separate circuit for heavy stuff (all single phase, mostly 3HP or equiv) - like the welder, air compressor, lathe, plasma, band saw... Currently I run a plasma with integrated air comp, but now I have decent air I could run a 'proper' plasma and increase my cut depth accordingly :) . I've labelled all the plugs which is a massive help when constantly unplugging/replugging stuff. Ideally I would just be able to have everything plugged in all the time.

Losses through the crappy plug circuit to my welder are causing me loss of penetration. If I had a girlfriend, I feel sure she would have left me by now...

I know NOTHING about electrics. Can someone tell me in a 'Ringo Star Reads: Thomas The Tank Engine' stylie exactly what to rig up - I'm talking wire sizes, plug types etc. I guess I need some really thick cable - there is a run of maybe 100 feet to the trip switches etc.

Jez had some good advice about using 'blue plugs' or something last time he was round, but I must confess I need a link or something to know what he's on about... What type of connectors have the lowest resistance?

Is there any danger when using 2 separate supplies/circuits in the same room?

Cheers, I dunno what I'm doing here at all... Al.

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Right,

I need some basic information

Size if the incoming supply(and earthing arrangement type), , length of run from the supply point to the garage, what cable you intend to run

ie ......

Steel wire Armoured (SWA) Reccomended

Pvc/Pvc

PVC Conduit etc

max load required ?

and I'll work out the supply cable size for you, taking into acount current requirments and voltage drop etc

Generally for the local circuits

its as follows :-

Lighting = 1.0mm'(6 Amp )/1.5mm'(10 Amp)

Sockets = 2.5mm'

16 Amp Sockets = 2.5mm'

32 Amp sockets = 6.0mm'

.....not taking into acount thermal constaints/lengh of run and volt drop etc...

Normal domestic sockets are only rated to 13 Amps, so your welder etc will require a 16 Amp (blue socket) or if its a biggy 32 Amp (Red Socket)

RCD protection is required for any socket outlet which has the potential to be used outside (these are UK BS 7671 Reg)

Oh before we go any further.....Is this for installation in the UK ?, if it is it falls under Part P of the Building Regulations

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Thanks very much guys.

Pugwash - I think you might be right, it's an option I'd thought about... Problem is, it's not my garage (belongs to my father, so not too bad). It may be possible, I'll do some asking...

Dumbass Q: if I did put 3 phase in (and it'd at least save me spending money on converting the lathe to single phase), how do I run single phase stuff - like all the lights and grinders and, well, everything I've got...? Can you just tap off a single phase circut from the 3 phase supply and have 2 sets of sockets? Apart from the lathe, everything I have is single phase, so I'm not sure of the worth/expense of this idea? Is it dangerous running both in one space?

Also, is 3 phase available everywhere? I.e. am I assured of being able to install it?

Les - sounds like you have some useful numbers!

Yes, this garage is in the UK. What do the building regs mean in real terms? The garage is supplied by a Mill which is a listed building, so I guess I have to be careful here (didn't want to make this too easy, eh?!).

Sounds a bit wishy washy, but max load would be whatever I can get - frankly I'd buy a plasma according to the power available. I suppose a max situation would be:

Lighting/sundry = 0.5kW

3 HP compressor = 2.5kW

Medium duty CNC table and PC (on the DIY wish list) = 0.5kW to 1kW

Plasma = 3kW +++ ? Size depends on what I can have really, more?...

The problem with kit like this (apart from the cost) is that it all needs to be running at once... :rolleyes:

I can't get more data until I'm back in the UK (Sept), I suppose the best method (since the main building is rented out to someone else) would be to get an entirely separate supply coming in, just for the garage. Is this comparable in cost to putting a 3 phase supply in? Are these supplies put in by whoever is the electricity supplier for the building? Or do you just get a private leccy bloke to come and install it all and hook up to the grid? Sorry, so many Q's.

So I can price up parts, is there a website with the 'red' type sockets etc? Can't see the point in going for blue and limiting it if the money is similar...? Also for the cable prices per metre (the big stuff).

I suppose I can just put an RCD on the incoming supply, regardless of its capacity? Safe is good.

Thanks again for any help. Al.

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Where in the UK are you going to be ?

Seem to remember you mentioning Minchinhampton :unsure: sometime ?

Part P is only applicable to Houses so does not affect you if its commercial :D

3 phase is available most places the only place it can get sketchy is out in the sticks on overhead supplies on the end of a line

You install a 3 phase distribution board with single pole MCB's for single phase supplies and 3 pole fopr 3 phase ;)

The maximum supply will depend on the maximum you can take from where you intend to take the feed from ?

Its no good wanting a 63 Amp supply if the maximum size circuit from the source is 32 Amp ?

A new metered supply from the local supply Authority (MEB, SWEB etc) can only be installed by them and by any "competent" person after the meter

If you are coming from an exsisting supply again any competent person can install it...but it needs to be tested to ensure compliance with BS7671 (IEE Wiring Regulations)

the type of RCD protection is govened by the earthing arrangment

Ie

TT requires both 100 Ma RCD (fixed equiment)and 30 Ma (socket outlets)

TN-CS and TN-S only require 30 Ma RCD on the Sockets

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Les - that's some kind of spooky memory you've got there!

In fact my father has a place in Minchinhampton, but also owns this Mill which is near Winchester, Hants.

I'll try to find out from the leccy company whether 3 phase is possible, and a cost. Or an extra single phase feed straight to the garage, if possible. Ok, it's not a house, so that's good with the Regs.

Earth... I'll try to find out. Any ideas what those acronyms stand for and if there is any easy way to figure out what its got???

Either way it sounds like I'd need the services of someone 'proper' - anyone know anyone good local to that area?

Cheers, Al.

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:D

First letter:

T The live parts in the system have one or more direct connections to earth.

I The live parts in the system have no connection to earth, or are connected only through a high impedance.

Second letter:

T All exposed conductive parts are connected via your earth conductors to a local ground connection.

N All exposed conductive parts are connected via your earth conductors to the earth provided by the supplier.

Remaining letter(s):

C Combined neutral and protective earth functions (same conductor).

S Separate neutral and protective earth functions (separate conductors).

Valid system types in the 16th Edition IEE regulations:

TN-C No separate earth conductors anywhere - neutral used as earth throughout supply and installation (never seen this).

TN-S Probably most common, with supplier providing a separate earth conductor back to the substation.

TN-C-S [Protective Multiple Earthing] Supply combines neutral and earth, but they are separated out in the installation.

TT No earth provided by supplier; installation requires own earth rod (common with overhead supply lines).

IT Supply is e.g. portable generator with no earth connection, installation supplies own earth rod.

Inside or nearby your consumer unit (fuse box) will be your main earthing terminal where all the earth conductors from your final sub-circuits and service bonding are joined. This is then connected via the 'earthing conductor' to a real earth somehow...

TN-S The earthing conductor is connected to separate earth provided by the electricity supplier. This is most commonly done by having an earthing clamp connected to the sheath of the supply cable.

TN-C-S The earthing conductor is connected to the supplier's neutral. This shows up as the earthing conductor going onto the connection block with the neutral conductor of the supplier's meter tails. Often you will see a label warning about "Protective Multiple Earthing Installation - Do Not Interfere with Earth Connections" but this is not always present.

TT The earthing conductor goes to (one or more) earth rods, one of them possibly via an old Voltage Operated ELCB (which are no longer used on new supplies).

There are probably other arrangements for these systems too. Also, a system may have been converted, e.g. an old TT system might have been converted to TN-S or TN-C-S but the old earth rod was not disconnected.

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Normal domestic sockets are only rated to 13 Amps, so your welder etc will require a 16 Amp (blue socket) or if its a biggy 32 Amp (Red Socket)

Les,

Don't want to start an argument or anything, but isn't the colour of a ceeform socket to do with the supply type? ie blue for single phase 240V, yellow for single phase 110V, Red for three phase 220/440V ? The size of the socket is related to the current rating - the most common being 16A (ie the type Caravans use) but I have used 32A, 63A ans 120A Blue ceeforms in the past, and the same in red for three phase...

Cheers

Mark

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Mark,

No you are correct, Blue is normally for 230 V and does come in several sizes right the way up

I was thinking along most of the welders we wire are either two or three phase....we don't really touch domestic stuff ;), so I had Red in me head :lol:

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Ok, I did some preliminary digging, me dear old pa is cool with the installation of whatever, so I 'can' do it.

I'll contact the company when I have the details in a few days, but... I just read this (admittedly from a phase converter selling company, so bound to be biassed):

"Users in rural or remote locations (or anywhere in the UK and Ireland) will find that a 3-phase supply is not easily obtained from their local power company. Installation costs in the UK range from 3000 to 72000 pounds."

OMFG. That's a lot of cash, isn't it! Is there any truth in the above? Does anyone have any idea of the costs I'm facing here?

Ta, Al.

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Ok, I did some preliminary digging, me dear old pa is cool with the installation of whatever, so I 'can' do it.

I'll contact the company when I have the details in a few days, but... I just read this (admittedly from a phase converter selling company, so bound to be biassed):

"Users in rural or remote locations (or anywhere in the UK and Ireland) will find that a 3-phase supply is not easily obtained from their local power company. Installation costs in the UK range from 3000 to 72000 pounds."

OMFG. That's a lot of cash, isn't it! Is there any truth in the above? Does anyone have any idea of the costs I'm facing here?

Ta, Al.

phone your local power supply company (mine is western power) and ask them to come out and have a look. I had a quote before they went ahead with the work.

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phone your local power supply company (mine is western power) and ask them to come out and have a look. I had a quote before they went ahead with the work.

Yup - I sure will, but was the cost for you anything between the above figures? Ta Al.

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Yup - I sure will, but was the cost for you anything between the above figures? Ta Al.

umm no

definitely not- i am pretty certain it cost £1200 including the VAT about threee years ago.

this included digging up the road and laying new cable- about 6 metres.

Of course this just installed a meter and a 3-phase main fuse box. Rest of the stuff was done by a real sparky!

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yay, thats my day job, DC to 500kV, switching to 1megV

Jez, anyone in their right mind can see it's a 1.21 gigawatts flux-capacitor.

With that thing running full pelt in a deLorean, I could really cut down on build time...

Hmm... B)

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I was contemplating building one for the roof of my 90......no, seriously!

I built a little TC 10kv primary, 200kv sec 1kva or so in the early 90's which was fairly cool. Something closer to the 1Mv mark would be cooler ;)

Used a DIY 0.1uF glass plate capacitor - which made worrying creaking sounds! (They have a bit of a rep for exploding)

Seems to me that with the advent of auction sites, building one with neon psu's and more off the shelf components will be easier!

Si

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