Garage "Bus Bar" and Cooker?

[markocosic]

Hi,


I'm about to revamp a garage (tiles, shelves, new lights, new sockets) and would like to run a "bus bar" (or whatever they are called) around it. Like you see in commercial/industrial buildings, a giant surface mounted conduit box with the sockets and light switches fitted into it.

I'd also like to run a feed for a (dual) electric oven into the kitchen next door.

The layout is as below:

http://www.cosic.org.uk/MarkoStuff/misc/1.gif
http://www.cosic.org.uk/MarkoStuff/misc/2.gif
http://www.cosic.org.uk/MarkoStuff/misc/3.gif
http://www.cosic.org.uk/MarkoStuff/misc/4.gif

Consumer unit is green in the first picture, the second picture shows the existing light switches (1x room, 1x bench both off one 10A MCB) and sockets (2x ring main, 1x welder 13A fused outlet like a cooker, one MCB for ring, one for welder) on the back wall and the door through to the house.

I would like to run that conduit with sockets in at a height of 1.2m off the floor, all around the back wall and consumer unit wall. (it could then kick upwards to go to the consumer unit, if necessary)

The cooker is on the other side of that back wall. It would need a new wire from the consumer unit. I'm fairly sure that there is room, will check and snap a picture of the unit in the morning. It's a 1990 house/consumer unit, and everything is on a 30mA or 100mA RCD.


Can the cooker cable run inside the conduit bus bar affair before going through the wall? It'd make life very easy if so!

In going through the wall and running a short while along the surface on the other side, what sort of conduit is required?

Any ideas where to buy the conduit bus bar affair as a retail customer?


Common sense, electrical design and physical implementation I'm fine with, sourcing bits and regs I'm unsure of as this isn't something I'd do every day!


I'd be after an electrician in Pembrokeshire to fill in the relevant paperwork/hook into the consumer unit too - any reccommendations for folks that have actual common sense/practical skills and not just a certificate? I'm after quick sanity check, rubber-stamp, flick the switch type stuff rather than them doing the work.


Cheers!

 

[sparkydude]

Hi the trunking you are after is called Dado trunking, or skirting trunking depending on the style of the lids, it comes in one, two and three compartment varieties although i think the dado only comes in 3 compartment . Yop can obtain it from any decent electrical wholesaler, but shop around as prices can be extortionate. Running your cooker supply through it is not a problem either. If it just for power, then i would use a 100x50 trunking with the relevant plates to fix your sockets to. If your considering running data,aklarm or tv cables aswell then you will need compartments.

Try CPC Farnell for trunking and see what they do.

Nick

 

[electronicsuk]

I'd be after an electrician in Pembrokeshire to fill in the relevant paperwork/hook into the consumer unit too - any reccommendations for folks that have actual common sense/practical skills and not just a certificate? I'm after quick sanity check, rubber-stamp, flick the switch type stuff rather than them doing the work.

Sorry Mark, this is a regular question round here and unfortunately an electrician is not allowed to certify work they have not completed themselves. You need to contact your local council building control who can inspect your work, but they will need to see it at first and second fix stages.

 

[RF Lighting]

It doesn't matter if it is in a special location or not. The creation of a new circuit is notifiable.

Maybe you should "get your facts straight"


As has already been said, decent electricians will not issue an EIC for work they did not carry out. Once you sign an EIC, you become responsible for the installation.

I know I would not be happy putting my name to an installation I don't know is actually safe.

 

[dingbat]

It is absolutely fine for a competent person to sign for the inspection and testing of an installation that has been designed and constructed by somebody else. But this is certification to (non-statutory) BS 7671 and has nothing whatsoever to do with the (statutory) Building Regulations.

What he cannot do is to self-certify that work as building regs compliant under his individual registration on a competent persons scheme. This is expressly forbidden under the terms of those schemes.

 

[markocosic]

but shop around as prices can be extortionatë

No kidding...

What is a fair price for say 100mm high, 50mm deep, plain and boring mild steel? Almost fell off my chair with what those I've phoned were asking!

If it just for power, then i would use a 100x50 trunking with the relevant plates to fix your sockets to.

Yes, just power really. I'd like to replace the two six-way extensions hanging off /every/ socket in the garage with some of this trunking with proper sockets sunk in. (whip off existing sockets, lay trunking over the top of the holes, bolt sockets back into the trunking along with half a dozen more) There's never more than 4kW running (say the welder and two 500W floods) but it's handy not to have to plug/unplug power tools, radio, computer, chargers etc all the time.

You need to contact your local council building control who can inspect your work, but they will need to see it at first and second fix stages.

Oh lordy, can of worms. What a load of <expletive> that part P is...

I'm happy to do everything bar actually hooking the cooker feed into the consumer unit - mainly becuase there's no flippin' switch between there and the meter.

What do you tell the council building control? "I'd like to nail some cable to a wall but not connect it to anything - please approve and subsequently inspect." Then call the union sparky to do the final hookup, with him self-certifying/signing an EIC for "fitting an MCB?"

 

[markocosic]

Things weren't quite as on paper as far as the circuits went - the lights are 5A MCBs rather than 10s and the 30A radial is the utility room (washer, dryer etc) rather than the welder. Paper almost matches the as-built, but no cigar LOL!


There appears to be a spare space in the consumer unit - ok to slot an MCB for a double oven in there?

(IMG_XXXX are small, IMG_XXXX-1 are large images)
http://www.cosic.org.uk/MarkoStuff/elec/

Wylex NN, with NB MCBs?

http://www.connectstores.com/P.E.D/sp_11801-10.html


And for something completely unrelated, how much power does a british standard snail draw?

http://www.cosic.org.uk/MarkoStuff/elec/IMG_5984.JPG

Electricity board were the ones who used a jackhammer to fit the cable rather than a cable gland - is it reasonable to ask them to empty snails/put a proper gland in or should I stick some expanding foam in teh gap and call it a day?

 

[Steve]

They wont gland it, its probably not SWA, rather concentric cable, which looks a little like co-axial aerial cable - it has a LIVE inner core and a combined neutral and earth concentric layer.

That picture makes me wonder - why are there snails here? Does the cutout get warm?

DONT use expanding foam. A couple of pieces of ply, carefully cut to match the cable and bolted through the plastic will do the trick. Anything you ask the DNO to do will cost you an arm and a leg, unless safety is at risk - it isn't.

Your consumer unit appears to have been installed before your cutout, since it has a time delayed main RCD - normally found on TT installs with an earth rod. You now have a TNCS supply, a much better earth, which doesn't need an RCD. Though you still need RCD provision for the socket circuits (provided by the L/H RCD)

Why is the CU so grubby? I'd be looking at replacing it, to be honest. You could enquire with your DNO as to the possibility of having an isolator fitted after the meter, many charge a fixed fee, of say £60 or so. Some do it free, some wont do it full stop.

 

[markocosic]

Presumably it's warmer where the cable is yes. They're everywhere round here though - getting to the front door at night is usually crunchy LOL! Will dig out some ply.


Everything was intalled Nov 1989 thru Jan 1990 and it's always been earthed by the cable/gas pipe.

LH RCD is for the stuff likely to get a saw through it (garage), soaking wet (utility/kitchen), or just plain sensitive (computer room, confusingly labelled bedroom there)

RH RCD is for everything else - bedrooms/living room with virtually nothing in, power for the gas boiler controls/valves, and the lights. RCD on the lights was a must, as we're all fairly tall (except mum!) and if somebody were to smash a light fitting with their face it wouldn't be the first time!

100mA was so that if the LH one tripped, the RH one would stay on to keep the lights on. In practice, as soon as the LH one trips it seems to take the RH one with it.


Grubby comes from being in the garage - lots of grinding/spray painting which covers everything in layers of dust, and lots of spiders that seem to love living in everything they shouldn't. Oh, and mum's too short to dust it... <runs and hides>


Will ask about an isolator - 60 quid ain't bad, and it'd make switchign that box (or fitting the coooker feed) that bit easier.

 

[Steve]

Your TIME DELAYED RCD is goosed if it trips when the 30mA one does, where the fault is on the 30mA side. Its time delayed for a reason.

Unfortunately they are rather expensive, I'd recommend you change the consumer unit from scratch (or get someone else to do it), its becoming slightly long in the tooth, and isn't really suited to its application.

You dont NEED a TD RCD if you get a new board. Just a split load with a plain mainswitch. Dont know why a TD was fitted if the supply has never been changed.

Your earth is NOT derived from the gas pipe. It is derived from the neutral of the supply cable, by a system known as PME - Protective Multiple Earth. The neutral of the supply cable is earthed at every possible point back to the substation, and at the substation. This provides a very good earth (and neutral) path, with very low resistance. It enables your MCBs to clear faults very quickly, and negates the need for any supplementary time delayed RCDs.

Your gas pipe is bonded so it cannot introduce a different potential into the house (the equipotential zone). It is an extraeneous conductive part.

 

[markocosic]

Presumably the TD was fitted because the sparky who wired the house was a bit of a numpty/this was the first RCD he'd ever fitted resedentially back in 89. Condensing boiler and pressuired spheres for the hot water/heating the plumber had to go on a course to learn about, the air filtration/heat exchagne/ventilation system confused the heck out of the builder, the BT guy cursed whoever specced engineering bricks for the outside of the house (destroyed his drill...), the carpenter had never seen a roof built for a 0.5psi pressure blast and the brickies had never seen anybody build insulation to scandanavian regs before.

Mixed bag to be honest - the 0.5psi is useful, given that nothing happened when the Texaco refinery blew up (others lost windows and roofing) and now they're building an LNG terminal nearby; everybody should have built in air filter/heat exchanger/ventialtors, as it kills smells and saves soo much dusting; the insulation was always good for laughs before (256 square metres chews about as much gas as a 2 bed flat and they'd always be cehcking the meter for faults, and indeed even replaced it once as it "must" have been faulty...) but now makes financial sense finally.

On the downside, the plumber made a hash up of the central heating install, the sparky seems to have fitted the wrong consumer unit as well as crummy lighting and the first of the condensing boilers fell to pieces almost annually...


Anyhow - back to the subject at hand:


Isloator between meter and RCD was 38 pounds from western power (electric supplier swalec) - tel no is 0845 601 3341 for reference.


New consumer unit then - what has similar cable layouts to what is already there? (I doubt there's much slack)


http://www.cosic.org.uk/MarkoStuff/elec/IMG_5979.JPG


Extra space for (1) cooker, (2) garage door opener/gate opener, (3) extra garage lighting, (4) external lighting would be useful, so 12+ ways handy.

 

[Steve]

Depends on your budget really.

Do you want individual RCD protected circuits? Or is a simple split-load board enough for your needs? Bear in mind each RCD and RCBO device costs about £40, and each plain MCB costs about £5.

http://www.tlc-direct.co.uk/Main_Index/Consumer_Units_Index/index.html

Look at MK, Wylex and Hager for ideas on price. Dont look at Contactum

Post links here of the setup you propose.

 

[markocosic]

A main switch RCBOs for everything would be nice, but lots of $$...


Do the following circuits make sense:

RCD 1 Max Power (W) Max Current (A) MCB Size (A)
1b) Cooker ? ? 40
2b) Radial Sockets - Utility Room & Shed ? ? 30 or 32
3b) Ring Main Sockets - Kitchen, Dining Room & Computer Room ? ? 30 or 32
4b) Ring Main Sockets - Garage ? ? 30 or 32
5b) Ring Main Sockets - Play Room ? ? 30 or 32
6b) Ring Main Sockets - Lounge & Bedrooms ? ? 30 or 32
7b) Garage Door & Gate Opener ? ? 10 or 16
8b) Garage Door & Gate Opener ? ? 10 or 16

RCD 2 Max Power (W) Max Current (A) MCB Size (A)
1a) Lights - Garage 1800 7.8 10 or 16
1b) Lights - Ground Floor 1200 5.2 5 or 6
1c) Lights - First Floor 800 3.5 5 or 6
1d) Lights - Utility Room & Play Room 250 1.1 5 or 6
1e) Central Heating Boiler & Pump 250 1.1 5 or 6

Notes
1b) Not yet fitted - to be double electric oven/grill
2b) Washing machine, tumble dryer and plus 13A fused feed to shed for lights/garden tools - RCD trip central...
3b) Fridge, freezer, kitchen appliances, hostess trolley, hifi/speakers/wifi router/phone base station/printer/screen/pc base/laptop/3x external hard drives/scanner etc - probably the most expensive circuit in the house...
4b) Welder, radio, battery chargers, power tools - noisy...
5b) TV, radio, iron, sewing machine, knitting machine, desk lights, phone base station
6b) TV, video, freeview box, phone base station, radios, hairdryer/straighteners/curling rolls, old PC
7b) Not yet fitted - but 2kW would be an absolute max
8b) Not yet fitted - but likely to be sizeable

1a) Not yet fitted - to be all HF flourescent battens
2a) 400W of compact flourescents in ceiling + doorbell & lighting sockets w/halogen uplighters
3a) 600W of compact flourescents in ceiling + attic aerial amplifier socket (naughty!) and lighting sockets w/bedside lights and bathroom shaving sockets
4a) All S/S flourescent battens
5a) Keep this with lights - don't want it going off!


Incomer-Fuse (60A)-Meter-Isolator-Consumer Units

Bring the isolator switch into a 100A, 30mA RCD to feed the eight circuits/spaces.

Use some 6mm^2 to connect a second, 32A+ RCD in parallel with it to feed the five circuits/spaces that would normally be left totally unprotected in a split-load unit.

Either bridge the inputs of the two RCDs or run a separate pair of tails from the main switch to it - will it matter either way?

This would mean that both need to be off (or the isolator switch) for all power to the house to be off, but does mean that you don't lose the heating/lights if something goes phut.


Heating, hot water, showers and hob are all gas and unlikely to change. Cooker feed, new garage lights/sockets, electric door opener/gate opener, outside lights are likely to be fitted in future.


A 17 way split load box:
http://www.tlc-direct.co.uk/Products/WYNHRS17SL.html

A 100A RCD to replace the main switch:
http://www.tlc-direct.co.uk/Main_Index/Consumer_Units_Index/Wylex_Rcds/index.html

MCBs to suit:
http://www.tlc-direct.co.uk/Main_Index/Consumer_Units_Index/Wylex_Ns_2/index.html


Would need re-labelling, and a note to ensure that nothing too juicy gets added to the lighting RCD.


Oh, and in answer to - does the cutout get warm - if a double oven were on/cooking going on whilst somebody were hammering the PC, somebody watching TV and somebody else welding in teh garage... ...probably!

 

[Adam_151]

It sounds like you really want something along the lines of hagers dual RCD board... designed for TT systems, mainswitch and 30ma and 100ma RCDS each feeding a bank of MCBS, not much room left for MCBS though.

Could have a main switch in a small enclosure, then to a henley block and to the CUs, each being fitted with an RCD incommer, to keep it neat, henley block in plastic adapatble box and tails in plastic trunking.

Not sure why you want RCD on everything though? belt and braces?

 

[Adam_151]

Definatly don't like the idea of 6mm² jammed in to feed the other RCD.

Other alternative to above if you definatly want to RCD everything is to set the board up as a split load with the split load kit, but have very few none RCD ways, but use one of them to feed a 32A/6mm² submain to a board right next to it, equiped with RCD incommer and containing the lighting circuits