Dual supply isolator and EDF

rustynails · Feb 6, 2014

Hi all,

I am being irritated by EDF at present. Last week I phoned them and asked them if they would be supplying a double pole isolator into the meter box between the meter and the consumer unit. They said in my area, Plymouth, it was our responsibility to fit a double pole isolator for the meter engineer to connect his tails to. It was also said that it was expected of us to do this, although I'm aware some actually provide it? So I installed a Wylex dual supply switch

Dual Supply REC Switch

and connected the tails from the consumer unit to the top. I've installed two sets of tails in total, one set for the consumer unit and one set for a future PV installation. Now, seeing as it was expected of us to supply and fit an isolator. I thought it best to fit the Wylex dual supply switch as I have only installed a standard dual rcd consumer unit, not a fancy wylex pv ready board etc. So that at a later date the PV could be added. The meter engineer turned up and threw his toys out the pram saying that the switch was not allowed in the meter box because it was our property. Well that's loverly but they told me to supply and fit a double pole isolator, where else was I supposed to put it.

So having been refused a meter on a brand new build house because the meter engineer didnt like the look of the switch installed. I have been on the phone and email to the EDF technical department. I got a response today saying this

"Most meter operators ask for a means of isolation on the load side of a meter, especially when the meter is installed in an external box, or cupboard. The advantage for the customer is the ability to de-energise there supply, making it safe to work on the consumer unit. Also as double insulated tails are being used, the switch provides a point of responsibility between the supplier and the customer. Looking at the photo, the only thing I noticed is that the isolating device is three phase. Normally the device would be a single phase switch.?"

I've attached the photo. It might look like a three phase switch but Im pretty sure it's not. It's voltage rating is 230v.

[ElectriciansForums.net] Dual supply isolator and EDF

rustynails · Feb 7, 2014

Engineer54 said:
Unless i'm mistaken, (it is early here lol!!) by the look of it, you have used one pole of each of what will be 2 DP switches. So i'd move those tails to accommodate the left two cable entries on that dual isolator, the right two entries will then be for your future PV system.

The switch has entries NNLL from left to right with busbar links inside. I actually think I've left a link in between incoming NN which should be moved to the outgoing NN.

Engineer54 · Feb 7, 2014

rustynails said:
The switch has entries NNLL from left to right with busbar links inside. I actually think I've left a link in between incoming NN which should be moved to the outgoing NN.

That's fair enough then!! Seems a strange way to to link the isolator out, confusing even!! lol!!

HandySparks · Feb 7, 2014

rustynails said:
The switch has entries NNLL from left to right with busbar links inside. I actually think I've left a link in between incoming NN which should be moved to the outgoing NN.

Fair enough. Just looked up the manufacturer's data on these; obviously designed for PV installation.

I'd leave the links on the incoming side. Otherwise, no point in having a 4 pole switch.

Knobhead · Feb 7, 2014

rustynails said:
The switch has entries NNLL from left to right with busbar links inside. I actually think I've left a link in between incoming NN which should be moved to the outgoing NN.

I think you're right. If you don't there is still a link between the two systems with the switch in the off position, not good for DNO personnels health.

7029 dave · Feb 7, 2014

jimjimjim said:
I think they've started doing this as standard. YEDL have done it on a couple of jobs last year and with yours that makes three, so therefore it MUST be the new trend. Looks sh1*e

Jim

They have been doing that in Milton Keynes for donkey's, plenty of external meter boxes there.

mechelec · Feb 7, 2014

7029 dave said:
They have been doing that in Milton Keynes for donkey's, plenty of external meter boxes there.

The cut outs are supplied screwed to the chipboard backboard which is cut to fit at an angle. The newer ones are on a DMC/ fibreglass type backboard.

rustynails · Feb 8, 2014

Tony said:
I think you're right. If you don't there is still a link between the two systems with the switch in the off position, not good for DNO personnels health.

It'll be like this once I take the link out down the bottom.

Knobhead · Feb 8, 2014

This is how I would do it. The back feed MCB as close to the CU as possible.
I don’t know how long the cable is to the PV unit. But it’s unprotected no matter what with your method.

Sorry to be a wet blanket. But even though I know little of PV systems, I do know about protection systems.

rustynails · Feb 8, 2014

Tony said:
This is how I would do it. The back feed MCB as close to the CU as possible.
I don’t know how long the cable is to the PV unit. But it’s unprotected no matter what with your method.

Sorry to be a wet blanket. But even though I know little of PV systems, I do know about protection systems.

Ok well, me too, I don't know much about PV either.. and I don't think I will installing the future PV system in this house either unless I spend a shed load of money and do the quals and pay more to elecsa. however I thought it best to provide the simplest solution for the pv bod. Buying a PV ready board was too much and over the top because the PV was best added later down the road. I saw a diagram in the wylex pv book, put the tails in to the loft and installed the switch. This is that diagram left side.