Consumer Unit

[JohnW2]

I'd much rather use that older Wylex unit than this newer type, from the same seller:
http://www.ebay.co.uk/itm/111599056328

Interesting. Isn't having separate RCDs for each socket outlet a bit OTT? If one were thinking of "newer types", why not:

...or ...

... at a fraction of the size?

Kind Regards, John

 

[ericmark]

I do like JohnW2 modern version. What I can't see is how it can be classed as a consumer unit. Which is a type tested distribution unit. I would not think it was made after the consumer unit took over from the distribution unit? Seem to remember about 1996? My understanding is the consumer unit is designed so unlike a distribution unit it can be worked on with supply to main isolator live, and does not require to be isolated else where? Can't see how this would fall into that description?

 

[JohnW2]

I do like JohnW2 modern version. What I can't see is how it can be classed as a consumer unit.

As a number of us have said or implied, it can't. That is an error in the title of the eBay listing. ... just as well, really (in England), since that could, in some people's minds, make the difference between installing it being notifiable or not-notifiable

Kind Regards, John

 

[AndyPRK]

I don't think any English man would put "shed distribution unit " into the Ebay search box

 

[JohnW2]

I don't think any English man would put "shed distribution unit " into the Ebay search box

Indeed (they're probably more like to talk about "fuse boxes" ). However, the item in question in no more a DB than it is a CU - as I said, the description is simply not correct - as has been said by myself and others, the item in question is a (rather bulky) RCD double socket - no more, no less, and nothing else!

Kind Regards, John

 

[PBC_1966]

I would not think it was made after the consumer unit took over from the distribution unit? Seem to remember about 1996?

As in the generally accepted use of the term with regard to the wiring regs? I believe the term came into use around the late 1940's.

But what does "consumer unit" mean to anyone who is not on intimate terms with the wiring regs. or the general U.K. electrical trade? I've always thought it a rather vague term anyway.

And as John alluded to, the building regulations stipulate that installation of a consumer unit is notifiable, but don't actually define what is meant by the term.

 

[ericmark]

I don't think until Part P building regulations anyone was really worried about what is a consumer unit or what is a circuit. If we look in BS7671 both are described, but circuit definition would include using a fused connection unit, and it seems these are not considered as forming a new circuit under Part P even if it does with BS7671. I think BS EN 60439-3 or IEC 61439-2 are the type testing refereed to? the former was 1989 it seems so got dates wrong. I know the Wilex fuse box in my house is not a consumer unit. The BS7671 only defines a consumer unit as a type tested distribution unit it does not actually say what the standard is.

The standard did change in 2001.

BS EN 60439-3 gives supplementary requirements for enclosed distribution boards (DBU) which are stationary, type tested assemblies (TTA) for indoor use, containing protective devices and intended for use either in domestic (household) applications or in other places where unskilled persons have access for their use.

Control and/or signalling devices may also be included. They are for use on a.c., with a nominal voltage to earth not exceeding 300 V. The outgoing circuits contain short-circuit protective devices, each having a rated current not exceeding 125 A with a total incoming load current not exceeding 250 A.

I was surprised at current rating I expected 100A. However the problem is Part P does not define the words used, so if not type tested then there is no restriction which seems crazy as it is the non type tested which are likely to have more danger if used by the unskilled installer.

The fact that the protective device was only a RCD and the over current was fuse in the plug plus not to BS EN 60439-3 it can't really be called a consumer unit even if it distributes to output to 2 plugs.

But the question of E-Bay search words does mean one has to select a name to attract buyers. Although it is a RCD socket that does not really describe it. Maybe a "antique commercial RCD protected BS1363 socket outlet metal" would describe it? But consumer unit will get far more hits.

 

[AndyPRK]

Antique wouldn't get many sales amoung the target customers!

 

[PBC_1966]

Antique? Something made in the 1980's or possibly early 1990's? A think that's stretching the definition of antique somewhat!

I know the Wilex fuse box in my house is not a consumer unit.

By what definition though? As I said, the term was in use decades before the wiring regulations became BS7671 and long before BS EN 60439-3, IEC 61439-2 or any other modern type-testing criteria were even thought about. The old Wylex standard boards with D.P. main switch and 4 or 6 fuseways were most certainly considered to be consumer units in their day.

I wonder how this would affect Part P notifications? If you're saying that an old Wylex standard board doesn't meet the current BS-EN/IEC definition of a consumer unit, does that mean you can install one without notification?

But the question of E-Bay search words does mean one has to select a name to attract buyers. Although it is a RCD socket that does not really describe it.

Precisely. It's more "consumer unit-ish" than the modern RCD socket, and in the eBay search world, it's the sort of thing somebody might stumble upon and decide is a better option after searching for "shed consumer unit" or "garage consumer unit" thinking that he would install a small unit with separate sockets. I think some people are being a little too harsh. (Although it would be nice if "ELCB" had the letters in the right order - Reminds me of the Morecambe & Wise skit with Andre Previn: "No, I'm playing all the right notes. Not necessarily in the right order....")

 

[ericmark]

(Although it would be nice if "ELCB" had the letters in the right order - Reminds me of the Morecambe & Wise skit with Andre Previn: "No, I'm playing all the right notes. Not necessarily in the right order....")

RCCB is what the manufacturer calls it. I do think the change from ELCB-c to RCCB to RCD and now RCBO without even considering the USA names must confuse people no end. As to a ELCB-v that would really confuse. Wonder if he sold it yet?

 

[PBC_1966]

RCCB is what the manufacturer calls it. I do think the change from ELCB-c to RCCB to RCD and now RCBO without even considering the USA names must confuse people no end.

I always felt those name changes were quite unnecessary, and in the case of the change to RCD, isn't the name rather vague anyway? Why change from Residual Current Circuit Breaker to Residual Current Device? "Circuit-breaker" was a far more descriptive term than the all-encompassing "device."

Isn't an RCBO a slightly different beast though, incorporating overload protection as well?

 

[ericmark]

I agree the RCBO is also a overload, however it seems some are unaware it is a RCD. When I returned from abroad in 1990 after 10 years away from the UK I found the RCD a massive problem. The site I worked on had current transformers in the WMDU (Weather proof main distribution unit) and some pots on the control board allowing one to select tripping current and delay. Normally set to 1A and 1 minute these then fed smaller panels normally fitted with 100 mA S type, which in turn fed consumer units with 30 mA units. But when a worked put in a nail to hang his coat on straight through the cable in cabin it still took out all three RCD's. But the real problem was not switching neutral fault finding was a nightmare.

At that time we still had a few ELCB-v around, and I remember being send out to companies caravan site to bond the caravans. I spent the day as instructed running earth wires from supply sheds to caravans, looking back it was rather daft as sure it was a TN-C-S supply, but at that time I just did as I was told. However my actions resulted in non of the ELCB-v's from working, and they all had to be swapped for RCD's.

Latter we seemed to move over to RCM units, some combined RCM with RCD and other were simply RCM's with IT supply, and we had to investigate the warning lamp. The combined units were good with a bar graph showing leakage so we were warned before it finally tripped.

I was rather surprised to find IT supply to control circuits and a RCM, but loss of power with the portable batching plant would result in a huge amount of work to remove batch as motor would not re-start under load. I personally don't think the German machine actually complied with UK regulations, I think although made in Germany it was designed for export to third world, and had been diverted to UK. Germans it seems do not mind breaking rules in other countries as seen with VW in USA.

 

[JohnW2]

I always felt those name changes were quite unnecessary, and in the case of the change to RCD, isn't the name rather vague anyway? Why change from Residual Current Circuit Breaker to Residual Current Device? "Circuit-breaker" was a far more descriptive term than the all-encompassing "device."

Indeed. Although it's not how we've come to use it, wasn't the intention that 'RCD' should be a generic term which covered a range of devices, and that the specific devices we now usually call RCDs should really have continued to be called ELCBs or RCCBs? As for the difference between the latter two, I suppose that if one is prepared to consider the incredibly unlikely, the 'residual current' does not have to be due to 'earth leakage' (or, in the US, a 'ground fault') - so, in that sense, RCCB is probably technically more correct.

Kind Regards, John

 

[ban-all-sheds]

No overload protection.

Doesn't need any.

 

[JohnW2]

No overload protection.

Doesn't need any.

In terms of what it actually is, I agree. However, in order to qualify as a 'CU' (per title of the listing), it probably would have to include some OPD.

Kind Regards, John