Consumer unit change, economy 7

[robo83]

Had a look at a job yesterday.

The consumer unit has 2 sets of tails feeding the board. 1 set left side into main switch supplying sockets, lights etc, 2nd set into rcd right side feeding the economy rate (storage heaters).

There is only 1 meter in DNO cupboard where all tails leave (meter just been upgraded by DNO) , is that acceptable. I am quoting to upgrade to 17th edition board as the existing is damaged.

 

[The Ghost]

Bit puzzled there is usually the economy 7 meter lurking somewhere to record the night-time usage, when I have seen this the meter is usually in with the timer switch and sealed. Happy to learn different. Maybe a new meter that records both?

 

[telectrix]

could be a dual tariff meter. automatically swtches in the meter.

 

[7029 dave]

Is it an integral meter with 5 terminals .?

 

[westward10]

Post a pic of the set up.

 

[telectrix]

you will have problems if trying to fit a single CU in this situation.

1 way would be to have 2 main switches, with RCBOs. but could you get enough division of circuits .

a dual tariff meter is better as then any electricity used midnight to 7 am is cheap rate, not just the storage heating.

 

[Octopus]

Wylex and others sell CU's specifically for such installs............. make sure you label both main switches.........

 

[westward10]

Yes you can get dual tariff boards.

 

[Midwest]

But they are pricy I seem to recall, the Wylex ones. Built to order I think. Best check

 

[westward10]

But they are pricy I seem to recall, the Wylex ones. Built to order I think. Best check

Yeah the Wylex Duplex range are pricey but I use them quite often and you get loads of internal space.

 

[robo83]

I just spoke to customer, it's a dual traffic meter. Supply on the cheaper tariff comes on at midnight.

Is it acceptable to use a normal split load consumer unit labeling up each side.?

 

[westward10]

No you will need a board with dual isolators and even though you could "adapt" a board I doubt the manufacturer would recommend this. You need a dual tariff consumer unit they are not uncommon.

 

[Octopus]

I just spoke to customer, it's a dual traffic meter. Supply on the cheaper tariff comes on at midnight.

Is it acceptable to use a normal split load consumer unit labeling up each side.?

Apart from the fact a split load or dual RCD board won't have 2 x main switches, you shouldn't put all the circuits on the same RCD

Electrium - http://www.electrium.co.uk/products/wylex/catalog?main=AAF&man=0150&sub=AAI&level=3

 

[westward10]

I have seen split load boards altered, not dual rcd whereby the rcd is replaced with a 60947-3 isolator and the linking kit ditched. I wouldn't recommend this though as it will hold no warranty.

 

[Midwest]

Yeah the Wylex Duplex range are pricey but I use them quite often and you get loads of internal space.

I also seem to recall, quite a lengthy lead time to build the thing as well. Probably attractive for Wylex if you want several, but not if you just want one. Think I was quoted several weeks.

 

[westward10]

I also seem to recall, quite a lengthy lead time to build the thing as well. Probably attractive for Wylex if you want several, but not if you just want one. Think I was quoted several weeks.

They are hard to source and are often built to order, been lucky on the last two as I have just Googled the rather lengthy part number and come up trumps with a wholesaler who has one.

 

[robo83]

I just spoke with the customer.

The off peak has only 1 circuit. There are 3 circuits on the off peak side of the board but 2 of them are unused as the storage heaters have been removed from the properly. It's just the water heater that's connected to off peak.

Is adding a second board for the off peak an option (local holesalers don't have dual tarrif)

I undestand modifying a split load board is not to spec but this would also work?

 

[telectrix]

best bet is to fit a standard CU and add a timer to the water heater.

 

[mhar]

With only the water heater on cheap rate, shouldn't the first thing that you do be to look at previous bills and make sure that having the off peak supply is in the customers interest?

 

[The Ghost]

Have they considered their daytime tariff as it usually quite expensive. And economy 7 is not economy below 4kw usage of night time heating/usage due to the day tariff. I think Mhar beat me to it.

 

[robo83]

Thanks guys.

I have emailed customer regards the unnecessary need for dual tarrif and await his reply.

If he agrees to revert to a standard tariff will it be a DNO visit or will they change the tariff electronically and I make safe the second set out tails?

 

[The Ghost]

The DNO would remove their equipment and quite rightly so.

 

[robo83]

If the customer wants to keep the dual tarrif.

Can I use a split load board for on peak, then add second smaller board for off peak with the storage heaters.?

 

[Richard Burns]

If the customer wants to keep the dual tarrif.

Can I use a split load board for on peak, then add second smaller board for off peak with the storage heaters.?

That is what I would do, the dual tariff boards are too expensive and not so useful for very different numbers of circuits.

 

[robo83]

Thanks Richard,

I've read also a few people buying the larger split load boards, 15 & 21 way as these have 3 neutral bars then adding main switch for off peak side.

I'm going with the 2nd board option, mainly as the job needs doing and I can't wait for dual tariff board to arrive, checked wholesalers and none of them stock.

 

[suffolkspark]

just fit a normal board, dual rcb or rcbos whatever you fancy, and fit a timer on the immersion as the others have said, go din rail mounted if you like, stick the un needed tail in a block? At least then you also have 1 point of isolation for the whole house which is always nicer

 

[davesparks]

Adding a timeswitch is not a sensible option, it will end up out of sync with the off-peak times and just add an unnecessary point of potential failure.
There is already a switched supply present which is only live during the off peak charging period so use it.

 

[mhar]

Use a wylex rec4 (not the tp&n one but the one correctly labelled for economy 7) external to the new cu, and virtually any high integrity board with enough ways. All day supply as normal, overnight goes to new (second) main switch and feeds an rcbo which utilises the seperate n bar in high integrity units.
Something like 16 Way Metal Dual Split Consumer Unit c/w 2 x RCD's c/w 12 MCB's - https://www.tlc-direct.co.uk/Products/BGDP18616.html will give you 10 split load day circuits plus 4 overnight rcbos (or different combinations) with no alteration to the manufacturers product, utilises the supplied conductors and busbar and complies with single point of isolation requirements

 

[robo83]

Quick update.

Went to the job last night.

I am Limited with space for the size of the CU.

I have spoken with the customer and it is likely that a 12way (10mcb) CU will be installed with one side RCBOs for on peak, the second side Off Peak, Main switch / RCD / MCB setup.

This isn't the cheapest option, but it keeps each side on a main switch and RCD protected.

Sound OK?