Cheap consumer units, who uses them, are they permitted?

[ericmark]

£65 fully populated with a single type AC RCD, no SPD still on sale at likes of screwfix, but can they still be used? In a caravan maybe? So no building regulations as not a building and the caravan site has a RCD as well.

But are these still being fitted in houses?

 

[markyd1]

No

 

[john4703]

I looked and thought a link might be good. I am not commenting on how safe they are
https://www.screwfix.com/p/mk-sentry-8-module-6-way-populated-rcd-incomer-consumer-unit/303kp

 

[flameport]

Ideal for people who want the cheapest possible tat and have no other considerations at all.

 

[JohnW2]

<pic> .... £65 fully populated with a single type AC RCD, no SPD still on sale at likes of screwfix, but can they still be used? In a caravan maybe? So no building regulations as not a building and the caravan site has a RCD as well.
But are these still being fitted in houses?

Well, at least it's metal - which probably makes it more compliant with one particular regulation than are the majority of domestic CUs in service today

I'm not sure what that particular CU is 'intended' for. Given that the highest rated MCBs are 2 x 20A ones, it seems fairly unlikley that it was 'intended' for supplying an entire domestic installation.

If it were one of two CUs supplying a domestic installation (equivalent to one "dual RCD" CU), then the only real deficiencies I can think of in relation to current regs would be the absence of an SPD and the Type AC RCD. You know my feelings about SPDs. As for the Type AC RCD, although that has been essentially non-compliant with regs (for new installation) for about a month, it is again the case that a very substantial proportion of UK domestic CUs currently in service probably have Type AC residual current devices.

The CU pictured is conceptually very similar to my daughter's (other than that hers has a couple of 32A RCDs and is plastic-cased) which was installed in 2004. - and I have to wonder in what senses, and to what extent, it is "less safe" now than it was considered to be less than 20 years ago.

Kind Regards, John

 

[ericmark]

I must agree the type AC RCD and the SPD requirements and usage is theoretical. Nothing is there to prove a SPD is required, and it would be hard to show really required. And throughout the last century we survived with RCD's never mind not using type AC, we only really needed RCD's to replace the ELCB-v's when it was realised there was a problem with them. Also type A is only good for 6 mA of DC, I tried measuring my installation and it was more like 9 mA however zeroing a clamp on DC ammeter is not easy so it may not be accurate.

So personally maybe type AC does need changing for some TT supplies where the RCD is the primary protection device, but with a TN system it should not be required it is just added protection.

However although it should be added protection, DIY electrics using plug in testers with loop pass in the main at 1.9Ω and the pass mark with a B32 on a ring final is 1.37Ω well I would say the old 1.44Ω is likely OK, it does say 3 - 5 times not 5 times, so minus 6% minus 5% = 205 volts, so 2.14Ω to 1.28Ω is required to trip the magnetic part of the MCB, so even at 1.37Ω worse case scenario still will not trip the magnetic part of the MCB.

However we are told the EV chargers and solar panels should auto disconnect if outside 207 - 253 volt RMS not sure were the 207 volts comes from? But it seems we are using near enough engineering?

 

[flameport]

I'm not sure what that particular CU is 'intended' for.

A quick way to dispose of obsolete items and still make a profit.
Take the items no longer wanted, shove them into a random assembly with other cheap pieces and sell it to people who don't know what they are buying.
It evidently worked as it's out of stock.

If people really wanted to pay that little for a consumer unit, they could have this for the same price: https://www.screwfix.com/p/mk-sentr...d-high-integrity-dual-rcd-consumer-unit/679vf
which although far from ideal, is a significantly better option.

not sure were the 207 volts comes from?

230V +/- 10%, the UK supply voltage limits.

Also type A is only good for 6 mA of DC

Type A RCDs are just a very small step on a long journey to devices which are actually suitable for modern electrical installations.
The UK is at the beginning of that journey.
Some other countries are further ahead.
None of them are anywhere near the end.

 

[plugwash]

AFAICT there is no law requiring compliance with BS7671 and even the guidance in the approved document only mentions "BS 7671:2008 incorporating Amendment No 1:2011." in England and an even earlier version in Wales.

Such a CU is clearly suboptimal but I think it would be pretty hard to argue that it did not satisfy "Reasonable provision shall be made in the design and installation of electrical installations in order to protect persons operating, maintaining or altering the installations from fire or injury." in a typical home.

 

[JohnW2]

A quick way to dispose of obsolete items and still make a profit. .... Take the items no longer wanted, shove them into a random assembly with other cheap pieces and sell it to people who don't know what they are buying. It evidently worked as it's out of stock.

I obviously cannot say that your cynical view is wrong, but I would still think that they must have believed that there was some valid need/market for a CU with such a combination of devices. That is particularly the case since, as you go on to say, for virtually the same price one can get something far more appropriate for 'a whole house' ...

If people really wanted to pay that little for a consumer unit, they could have this for the same price: https://www.screwfix.com/p/mk-sentr...d-high-integrity-dual-rcd-consumer-unit/679vf
which although far from ideal, is a significantly better option.

I presume that the only reasons why you regard that as 'less than ideal' are the absence of an SPD (which, as you know, I personally consider irrelevant) and the fact that it uses RCDs+MCBs, rather than RCBOs (which many people, including the regs, would consider quite acceptable).

On reflection, I suppose that a CU such as eric illustrated might have been 'intended' for small flats or suchlike. I've seen such things used for individual rooms in hotels, student accommodation etc.

Type A RCDs are just a very small step on a long journey to devices which are actually suitable for modern electrical installations. The UK is at the beginning of that journey. Some other countries are further ahead. None of them are anywhere near the end.

To my mind, the question is whether it is a necessary journey - i.e. a journey which significantly benefits anyone other than those who manufacture, sell or install the devices.

I would be very interested to know how safety-related statistics (electrical injuries/deaths and {definitely} electrically-initiated fires etc.) in "those countries which are further ahead" compare with those in the UK (and I have my suspicions about what those statistics might show).

Kind Regards, John

 

[EFLImpudence]

230V +/- 10%, the UK supply voltage limits.

It's 230V -6%/+10%

 

[SUNRAY]

A quick way to dispose of obsolete items and still make a profit.
Take the items no longer wanted, shove them into a random assembly with other cheap pieces and sell it to people who don't know what they are buying.
It evidently worked as it's out of stock.

The reason it's out of stock is they sell so many of them their supplier is struggling to keep up.

The manufacturer/supplier will, I'm sure, vehamently dispute the claim any of the contents are in any way obsolete.

 

[ericmark]

We don't have any completely safe systems, I see Welsh goverment want 20 MPH speed limits, next is man with red flag, but in the main some compromise is required.

The TN-C-S seems however daft, and I can't see the point of RCD's AFDD's SPD, etc while still using TN-C-S first things first.

But Gov it seems has not got a clue, they seem to think smart meters can turn lights on/off by clapping hands.

 

[SUNRAY]

We don't have any completely safe systems, I see Welsh goverment want 20 MPH speed limits, next is man with red flag, but in the main some compromise is required.

The TN-C-S seems however daft, and I can't see the point of RCD's AFDD's SPD, etc while still using TN-C-S first things first.

But Gov it seems has not got a clue, they seem to think smart meters can turn lights on/off by clapping hands.

Indeed no completely safe systems...

Despite 'the authorities' declaring smart motorways safe, the whole of the smart motorway control system failed recently, I believe it took something like 6 hours to get it back up and running.

 

[JohnW2]

We don't have any completely safe systems, I see Welsh goverment want 20 MPH speed limits, next is man with red flag, but in the main some compromise is required.

We have plenty of 20 mph limits around where I live, and I personally find them positively dangerous - the only way I can attempt to keep to such as speed in a 21st century car is by spending 90% of my time looking at the speedometer and 10% of the time looking to see who/what I am about to hit!

Kind Regards, John

 

[SUNRAY]

We have plenty of 20 mph limits around where I live, and I personally find them positively dangerous - the only way I can attempt to keep to such as speed in a 21st century car is by spending 90% of my time looking at the speedometer and 10% of the time looking to see who/what I am about to hit!

Kind Regards, John

I point I have raised with my MP.

Additionally it seems some pedestrians treat such limited roads as pedestrianised.