Timer on CU (with pictures :)

[DJM]

I know you like pictures so here are some to go with my question.
I have been asking about connecting two ovens and had thought I had 2 CU spaces, but on checking, these appear to be in teh CU controlling the storage heater, which appears to be connected to a timer. We have never used the storage heater and the only time we even tried it was during the day and it didn't work. But, now looking at the CU I am assuming that this CU will only be powered in the economy 7 hours and controlled by the timer. So my questios are
1) Is my assumption correct that the CU will be live as controlled by timer?
2) Who "owns" or is responsible for the timer?
3)We still benefit from cheaper night time electricity on non-storage heater usage, and as we don't need the storage heater, can the CU be changed to be active 24/7?
3) If not any other sensible way I can free up CU space for the new ovens?
Please don't say full re-wire as this is neithr practical nor affordable at the moment.

Timer and CU to storage heater (fuse cover removed)

Input to timer (and rats nest of earths)

CUs, timer and meter (prior to labelling fuses)

No free slots in eitther the white MEM or grey Wylex house CUs
2nd smaller grey Wylex bottom left feeds the outhouse[/img]

 

[DJM]

Oh, forgot to say that I have been trying to get a sparky interested in coming and having a look and advising, but there is obviously no shortage of work in my area as they all appear too busy or dis-interested. Neighbours, friends and family have had no electrical work done recently so can not recommend anyone, so any advice how I can
1) find a good electrician
2) Find one willing to come and have a look
I am assuming that having a look will involve a fee

 

[Adam_151]

That Timeswitch is owned by the DNO and engergises the eco7 by pulling in a contactor, it also I belive switches the meter over to lower rate (there seems to be a thin grey cable between the two) I'd have thought the modern meters would have inbuilt tele-switches, but I dunno, I'm sure Roo will know though

You could change that baord over to 24/7, but whats the point, you may just as well get a new board and connect it with the henley blocks in the middle, but there isn't enough room in them I think

Personally depending on what the state of the wiring is, I'd try and replace at least one of the existing boards with a new one, I'd probably go for at least the top grey wylex, and if not the white one as well (looks like it might be of the age where it might feed VIR), then leaving enough ways so it can be eliminated at a later date

I've got deja vu!... I'm sure I've seen this electrical cupbaord before *scratches head*

 

[DJM]

This kitchen has been a long drawn out affair and one of the drivers is the electrical cooker connections. In a previous thread I started about Peridic checks I posted the overall cupboard pic which Adam commented on.

At the time we were looking at a single range and was intending to upgrade the existing 10mm to 16mm so the current issue didn't arise. Unfortunately type of range SWMBO wants is not available so we are now into the hob and 2 sigle ovens scenario, which is why I was looking for 2 spare CU slots.

Replacing the MEM and large Wylex is a complete house re-wire as the small grey Wylex CU feeds the outhouse and the cream Wylex runs a single storage heater (which is never turned on). As such this isn't really tenable at this time. The MEM does have 2 old lighting runs, but the rest are in relatively new cable.

As you say the Henly block is full. Can I get a larger henly block, or piggy back installed to add a small CU and then perhaps run the whole cooker set up (hob, oven 1 and oven 2) from it? That would free up a slot in the large grey Wylex.

 

[Adam_151]

Is there a place where you could site another board? and cable up circuits easily enough?

Perhaps fit a small split load board for the kitchen circuits (perhaps even a large one and have a lot of spare ways), do a complete re-wire on the kitchen, Once the old cooker circuit is gone, feed the white CU from the cooker way on the wylex for now?

Whats the wiring like to outbuildings?

 

[DJM]

Due to the house layout and concrete flooring, the cupboard is really the only viable place for CU. Anywhere else and the upstairs is either fed through bathroom or would have to go underconcrete to go up and around. Cupboard minimise this.

Thats why I suggested another small 3 way CU to run just the cookers if another feed is possible. That way, the freed space in the wylex could be used to replace one of the MEM slots which is old in the short term.

Kitchen ring already on it's own slot and outbuildings fed by the armoured cable and all looks reasonably new.

 

[Adam_151]

I'm talking around room in that cupboard
Seems like while you could perhaps get a board in, it'd be difficult to get the cables to it? from what I can see, but obviously I'm not there

If it were me then, I'd fit a new board for the kitchen, but go for a bit more than 3 ways, I'd move the kitchen ring final over, and I'd put a new circuit in for the kitchen light, just to keep it all together and make sure the kitchen circuits never have to be touched again

Consider also whether you need a non RCD circuit for the freezer

So 6-way board that takes RCBOs , so looking at somehwere around "H x W x D: 230 x 230 x 110mm." for a 6 way (after main switch) going on the size of MK kit

Could even replace the board for the outbuildings with a larger one

 

[JohnD]

You already have 3 CUs, the last thing you need is another.

Get one nice big one. A dozen ways is common, some people have 16 ways, mine has 22 which I find ample Get a good brand so you can get parts and RCBOs easily.

If you really have to, you could get a new big one to replace one of your old CUs and put your new circuts into it as well, while having room to have the circuits transferred from the other old CUs later (buying a good big CU is not much more expensive thatn buying a little one, since you are just paying for a bigger plastic box and some fresh air).

btw you could easily tidy up your earths, just get an 8-way earth block and put it near the cutout, run all your CU earths and main bonds into that.

You also ought to have a 100A main switch to isolate your entire installation in case of emergency or maintenance, fitted after the meter and before your Henleys.

If you ask your supplier they might give you a PME earth for nothimg or £60, and perghaps fit an isolator for you as well.

 

[Softus]

Would you recommend RCBOs over MCBs, John?

 

[JohnD]

That's a very good idea.

 

[Adam_151]

That would indeed be the preferable option John, but the impression I get from the OP is the existing circuits arn't upto much and arn't fit for anything but ripping out, but he cant afford that at the moment?

DJM, it might be better if you go into more detail about what the existing wiring is like, it doesn't give to be spot on, but it does have to be reasonably safe for modifications to be carried out on them and test out ok (but if its VIR thats going to fall apart the moment its taken out the CU, best leave well alone until you can rip it out and start over, which ought to be ASAP)

 

[JohnD]

'mmm, could be. Looking again, I see he actually has 4 CUs (!) the two small Wylexes look like current model, the grey metalclad is a late one with a way for a 45A fuse; the rewirable MEM is the oldest, IIRC it has porcelain fuseholders and exposed terminals when you open the front cover. I could only see PVC cables that look fairly modern, but, looking again, I can't see any final circuits from the MEM or the metal Wylex, and these are likely to be the oldest ones.

I still like the idea of putting in a new CU to accomodate the new circuit(s) and take over from one or (better) more, of the old ones.

Seeing all those CUs reinforces my belief that we should put in excessively big ones with lots of room for expansion.

@ DJM, is one of those CUs exclusively for Night Storage heating, and do you still use it?

Can you post a pic inside or around the two upper CUs so we can see what the wiring is like?

 

[Adam_151]

John, the bottom 3 way wylex standard next to the timeclock is for the eco 7 storage heater, I think the OP wants to loose this eventually (You got gas CH, DJM?)

I'd also like to see inside those top two CUs, and a list of whats on each wouldn't go amiss

Edit: Look at those tails into the top grey wylex, I wonder if the metal has a slot cut....

 

[DJM]

Thanks for all the feedback. Really helpful.

I would love to get a single large board with expansion ready for re-wiring as we can do it, but there is no space for a big one in the cupboard without re-locating something already there. And if they are re-located, then electrician will have to check all circuits and then might as well re-wire to new board which pushes into re-wire territory. I could find room for an MK 6 way, though it wouldn't be best positioned down to the right of the cream Wylex.

MEM is pretty much as John says and would be the one I'd most like to lose. But it is the most difficult to accomodate due to cost and disruption

Fuses L-R
30A rewirable - downstairs ring - but only residual (4) sockets not moved to grey wylex
30A rewirable - upstairs ring
5A rewirable - downstairs lights front house (old possibly VIR from CU but in stable condition and properly secured.
5A rewirable - upstairs lights (old possibly VIR from CU but in stable condition and properly secured. At ceiling roses I have checked, cable is PVC)
5A rewirable - downstairs lights back of house inc Kitchen
20A rewirable - immersion heater

Large Grey Wylex

Fuses L-R
45A cartridge - 9.5kW shower (6mm pvc)
30A rewireable - downstairs ring kitchen (inc boiler in garage) (pvc)
30A rewireable - downstairs ring front house (pvc from CU not checked sockets, but all sockets look quite new)
30A rewireable - loft extension (pvc)
45A rewirable - cooker (10mm pvc)

Small Grey Wylex
bottom left with armoured cable

30A rewireable - outhouse
30A rewireable - conservatory

Small Cream Wylex
linked to E7 timer

20A cartridge - single storage heater (pvc)
spare
spare

I have been away on business the past couple of days so some of this is from memory and the pics I have already on the laptop. I will have a closer look tonight in the MEM.

 

[JohnD]

I'd think about replacing the grey metal Wylex. It's very big, and it shouldn't have two 45A circuits on it. the cables don't look bad.

p.s. Adam is referring to the fact that it seems to have the Red and the Black supply going in through separate knock-outs. In a metal enclosure magnetic effects mean this leads to eddy currents and overheating proprtional to curent drawn. It's a mistake more often made by amateurs. It might be interesting to feel for heat when the shower and cooker are going.