Sourcing our Electrical equipment

[JanetE]

We are in the process of purchasing our electrical equipment and wondering where to source this.  Looking at CPC which seems to be reasonable.

Also our electrician is keen to have the front mounted plastic patress boxes (dry lining boxes) and I am also interested in which are the best make to get.

Very interested in the general consensus 

[ProDave]

First, if you want dry lining boxes, then without a shaddow of doubt get Appleby. They never give trouble, unlike some other makes which can be dire.

I buy a lot of stuff from CPC, and I also use Screwfix (electricfix),  toolstation, and TLC direct.

I also buy a surprising amount from ebay, e.g I can't find anywhere else where I can get smoke heat and CO alarms as cheap.

[Onoff]

Have  a look at these 2 suppliers:

http://www.ukelectricalsupplies.com/

http://www.fastlec.co.uk/

[Jeremy Harris]

One thing to watch is VAT receipts.  I've spent the last few days collating our VAT reclaim and virtually no ebay sellers give a VAT receipt, and without the supplier's VAT number you cannot make a claim, I've found.  I'd guess we've "lost" a fair bit of VAT as a consequence of this, as I bought quite a lot of electrical stuff (loads of Crabtree Starbreaker RCBOs, for example) from ebay.

The same goes for Fastlec and TLC, they give you a VAT receipt most of the time, but I've had 2 or 3 receipts from both these companies that were emailed with no VAT number.

[Guest Alphonsox]

We've found the same - I have had to go back to a number of companies selling on Ebay and request VAT receipts, I have no idea why they don't do this as standard.

[joe90]

I am about to buy electrical stuff for my workshop and was going to use screwfix but CPC are much cheaper, is Marbo stuff Any good ? I am looking at metal clad sockets and switches in particular.

[reddal]

25 minutes ago, Alphonsox said:

We've found the same - I have had to go back to a number of companies selling on Ebay and request VAT receipts, I have no idea why they don't do this as standard.

One of :

1. They aren't VAT registered. In which case fair enough - though they should make clear that the price doesn't include VAT.
2. They are VAT registered - and pay the VAT in their VAT return - but they aren't very organised and don't send out invoices.
3. They are VAT registered - but just pocket a lot of VAT on ebay sales and never declare it. I bet a lot of that goes on. They will be in trouble come an audit.

I have the same trouble with Amazon purchases all the time. Its not always clear if the price includes VAT - and even if it does you have to hassle them to get an invoice.

OMG - you reminded me its quarterly VAT return time again. I hate the whole process...

- reddal

[ProDave]

57 minutes ago, joe90 said:

I am about to buy electrical stuff for my workshop and was going to use screwfix but CPC are much cheaper, is Marbo stuff Any good ? I am looking at metal clad sockets and switches in particular.

Marbo used to be Volex / Wylex in disguise. At least they used to sell Marbo consumer units that were ideniticl apart from the name stamped on them to wylex boards.  It's fair to say they are at the budget end.

For my money, I will but using Scholmore Click Mode switches and sockets. Very cheap, but quite nice looking and well made.

[Onoff]

Click Mode or Hager Sollysta for me.

Volex are the spawn of the devil. Terminals too tight to get x2 2.5 including the insulation on some let alone spur off it.

[Guest Alphonsox]

What are the current recommendations for Consumer units and RCBOs ? We are going to need to think about purchasing soon.

[ProDave]

I still like Hager, mainly because they keep the design of their stuff consistent, unlike some others. e.g fit a new MK mcb in an old MK board and it might as well be a comnpletely different make as they keep on changing the design.  I have a Hager in my new house.

I have fitted a couple of the BG new metal consumer units and I liked the ease of knocking out the knock outs, and the fact the top and bottom entry knockouts were mostly 20mm round, perfect for terminating SWA.

My Hager CU is an "old" one that has a metal back but plastic front, I made sure it was fitted last year before the new regs came into force. I am flush mounting it, i.e the back of the CU is screwed to the OSB "back" of the service void, and when battened and plasterboarded, just the plastic front of the CU will show in front of the plasterboard.

 

[Gone West]

I bought most of my first fix electrical stuff from TLC. Bought Schneider sockets, light switches etc and lights from a local electrical store that did a really good price.

[Guest Alphonsox]

Has anyone used the Pro-elec stuff ? CPC currently have some very cheap deals e.g. RCBOs for £10.50 singles or £8.95 3+

[ProDave]

24 minutes ago, Alphonsox said:

Has anyone used the Pro-elec stuff ? CPC currently have some very cheap deals e.g. RCBOs for £10.50 singles or £8.95 3+

Yes, cheapest of the cheap, but having said that I have installed a few and never had any faults.

[Onoff]

On 5 June 2016 at 16:31, Alphonsox said:

What are the current recommendations for Consumer units and RCBOs ? We are going to need to think about purchasing soon.

Metal for a start to comply with Amendment 3. I'm NOT a Wylex fan tbh but this PDF gives a broad what's what and why. In my own (and many others) humble opinion the best way to fully comply with the regs and minimise inconvenience is to have the "all independent circuits" configuration i.e. every circuit on its own RCBO. Go even further and put the freezer on its own RCBO etc. On what circuit to put the smokes/CO2 can be controversial. Everyone will have their own interpretation.

http://www.electrium.co.uk/media/20150624085516_0_WylexNMMetalConsumerUnits.pdf

Gets more complicated with a TT earthing system when there is a very good argument for having Double Pole RCBOs. The big names tend not to do DP RCBOs in single module width so with them you'd end up with a massive board. There are compact, single module, true DP RCBOs but it means venturing away from the main brands. But on the basis they're all made in a factory in China and then look at the "issues" the big names have had over the years then why not! Personally I like Hager. They just look and feel like a quality item. I have heard of issues even with them. Second for me would be Schneider (as was Merlin Gerin).

[Guest Alphonsox]

The plan is to go for RCBO on everything - however the number of circuits has mushroomed so this won't be cheap, hence my interest in the dirt cheap Pro-Elec RCBOs. We have got a PME installation for reasons that entirely escape me, I was expecting TT but NIE decided otherwise.

[ProDave]

By shopping around and buying some job lots, I put my Hager CU together with 13 circuits all rcbo's for a total of £80, all from ebay.

[JanetE]

This has been very helpful, thanks to all. Moving on to plumbing........ 

[TerryE]

1 hour ago, Alphonsox said:

We have got a PME installation for reasons that entirely escape me, I was expecting TT but NIE decided otherwise.

We used to have TT, but because of load mis-balances across the phases along the street our neutral would often lift 6-8 V about ground earth.  So a short between N and E would be enough to trip our main RCD.  What a pain.  We haven't had any probs since we switched to PME.   

[Guest Alphonsox]

We have our own dedicated transformer (freshly installed) mounted on a pole around 60m from the house. In every other similar installation I have seen in the area this would have been done as TT setup. I was surprised when NIE informed me that they would install PME, Our sparky was even more surprised and told me they had made a mistake and sent me back to reconfirm. I was told this now standard practice and that they would always install PME if there was space available.

[Jeremy Harris]

I believe that one change has been that the DNO now is better at tying the N to a decent E at the transformer, so lowering the impedance and making TN-C-S as "good" an option as TT.  If Ze (the earth impedance) is too high (above 0.35 ohms IIRC) for a TN-C-S arrangement you can always add a local earth rod in parallel with the earth (N) connection at the incomer to reduce the local earth impedance to a lower value (a good idea to have Ze as low as possible, in my view).  

Also, bear in mind that the critical factor as far as fault current is concerned is the fault loop impedance, Zs.  It is Zs that will determine the maximum voltage rise at the PE/N of the RCD/RCBO and so determine the time taken to trip to some extent.  In addition to sizing all the conductors appropriately (to reduce Zs) having as low as possible Ze at the incomer helps, as does having fatter and shorter cables after the incomer.

The main issue with TN-C-S is if you have outbuildings with a long cable run from the incomer.  In this instance, the additional cable impedance on either TN-C-S or TT (but it may be a bigger issue with TN-C-S because of the additional distance of the exported earth back to the sub-station transformer) can increase Zs at the remote end of the cable.  You can always add an additional earth rod at any outbuilding to lower Ze locally and hence lower Zs on all the outlets in that outbuilding.  This is what I've done.  We have an incomer that is TN-C-S and because we have a fat (25mm²) three core SWA feed from there to the house, we have maintained a low Zs at the house.  The garage has a 4mm² SWA feed, and although Zs remains within limits it is higher, because of the thinner cable, so the RCD in the garage could be a bit slower to act in the event of a marginal fault current.  I fitted an earth rod and additional earth cable to reduce Ze at the garage CU, so reducing Zs and decreasing the fault operation time of the garage RCD.  I did this solely because the garage will be used as a workshop, and there will be machine tools running in there, so the likelihood of there being a fault seemed to me to be a bit greater.

[ProDave]

Calling a TNC-S connection to a single dwelling "PME" is a bit of a misnomer.  Pme stands for Protective Multiple Earthing, and is an extension to TNC-S (you can have a TNC-S supply that is not PME)

In a normal network like where I am, one transformer serves 8 houses. As well as an earth at the source, there is an additional earth where the cable to each house feeds from the network. this is usually laid horizontally in the trench next to the distribution cables.  At the transformer there are usually separate HV and LV earths.

In the case of a transformer feeding a single house there's not much chance for much in the way of multiple earths.

The big difference between TNC-S and TT is of course the combined neutral and earth connection. That coupled with the DNO almost exclusively using concentric cable, presents a potention (pun Intended) problem. It is not unheard of for the outer core of a concentric cable to corrode and break. If that were feeding a TT earthed system, then your stuff would just stop working, but your house would remain earthed to local earth.  In the case of TNC-S the multiple earthing system tries to carry the neutral current instead, and your "earth" potential can rise considerably. Not a problem inside a house, but can be a problem with outbuildings and it definitely a serious isue with a metal skinned caravan (step out of the door, one foor on real ground, one hand touching the metal skin of the 'van - ouch) which is why you must not connect a caravan to a TNC-S earthing system.

But generally don't worry about it. As already said you can supliment the PME earth with your own local earth rods.

[Jeremy Harris]

My understanding is that officially PME stopped being a terms to describe an earthing system when we harmonised our regs with the EU, and adopted the "T" standards across the board.  Apart from anything else, the new designations (not that new, they came in when we changed to harmonised cable core colours, IIRC) are far more logical, in that every letter in the descriptor has a defined meaning, unlike PME, which could well not mean "multiple" at all in some cases, as you say.  I'm not even sure that our TN-C-S system is PME, as I have a feeling we're the only house fed from that phase on the nearby sub-station transformer.

 

 

[Guest Alphonsox]

I thought in the general case using supplementary earth rods for PME was frowned upon. The argument being that you don't know anything about the number or condition of the Multiple Earths and hence in a fail condition your local rod could end up being the sole earth point for your street.

[ProDave]

The DNO don't work to BS7671, if they did, they wouldn't be using concentric cable. They have (make up?) their own rules.