Off peak supply and on peak in one board

[newfutile]

In the above board with 2 main switches but only 1 neutral bar.
What is the best way to wire the neutrals of the rcbos that feed the 3 storage heaters?

 

[Murdoch]

Why are RCBOs being fitted?

 

[newfutile]

we fit rcbos for additional protection on all out domestic consumer units.
the issue is there is only 1 neutral bar

 

[ProDave]

Picture of the board please?

 

[binky]

could you cut the neutral bar?

 

[SPECIAL LOCATION]

In the above board with 2 main switches but only 1 neutral bar.
What is the best way to wire the neutrals of the rcbos that feed the 3 storage heaters?

Are you saying you have two "main-switches" wired in parallel to the same neutral bar?
Or if not how are these two main switches connected?

If connected in parallel how are you meeting compliance with 461.1.201.
i.e. either switch should be able to disconnecting both live conductors of a single phase supply?

Basically to my understanding any isolator switch must disconnect both the Line & Neutral conductors from its respective source of supply. (Standard/Off-Peak/PV/etc..)

I suspect you could be looking at the wrong end of the problem..
e.g. If you are satisfied that the 'main-switch' arrangements meet BS7671 then I don't think you will have any issues with terminating any RCBO neutral fly-leads.

Isn't this just a variation on the old landing light borrowed/shared neutral problem..
Two sources of supply can energise the same neutral conductor?

 

[ProDave]

In the absence of a picture yet, we can only guess.

My guess is there are 2 live tails into the CU and only one N tail. Only one of the main switched has the N tail connected and that one disconnects N for peak and off peak circuits.

If I am right you need to daisy chain the single N tail to both main switches and then a separate N bar for peak and off peak. I keep a box of "CU spares" including N bars and brackets so would soon be able to sort something out.

 

[Phoenix]

Other than it would be a little awkward to make the busbars work and would probably require a short tail and a connection block. Presented with that arrangement ofincomming conductors and single neutral block. I guess electrically, there would probably be nothing wrong with having a three pole main switch and a single neutral bar for all the cirucits

 

[SPECIAL LOCATION]

In the absence of a picture yet, we can only guess.

My guess is there are 2 live tails into the CU and only one N tail. Only one of the main switched has the N tail connected and that one disconnects N for peak and off peak circuits.

If I am right you need to daisy chain the single N tail to both main switches and then a separate N bar for peak and off peak. I keep a box of "CU spares" including N bars and brackets so would soon be able to sort something out.

As per Twatt-Daves observations this really shouldn't be too much of a problem to resolve for anyone competent to work on domestic CU's?

Unless of course you are new to the game and haven't yet cut-your-teeth on some less standard and/or a bit obscure arrangements?

What is your background Newfutile?

 

[SPECIAL LOCATION]

Other than it would be a little awkward to make the busbars work and would probably require a short tail and a connection block. Presented with that arrangement ofincomming conductors and single neutral block. I guess electrically, there would probably be nothing wrong with having a three pole main switch and a single neutral bar for all the cirucits

Now that is just "thinking-outside-the-box"..

Is that allowed???

Or should we be haggling for a life ban with the admins????

 

[binky]

Now that is just "thinking-outside-the-box"..

Is that allowed???

Only if it's metal....

 

[newfutile]

I'm a Qs with a housing association,I replaced 2 old Consumer Unit with a new fusebox 21 way which I added another main switch for the off peak,it has 2 lines and 2 neutrals but only 1 neutral bar, my concerning is operating the off peak main switch will make the neutral bar live after midnight, should I run another conductor bar or connect the 3 storage heater neutrals into the bottom of the off peak main switch?

 

[poni]

I'm a Qs with a housing association,I replaced 2 old Consumer Unit with a new fusebox 21 way which I added another main switch for the off peak,it has 2 lines and 2 neutrals but only 1 neutral bar, my concerning is operating the off peak main switch will make the neutral bar live after midnight, should I run another conductor bar or connect the 3 storage heater neutrals into the bottom of the off peak main switch?

if you added another main switch then you should have fitted another Neutral bar , I do have one question how are you going to meet the isolation requirements?(SOLO)

there would probably be nothing wrong with having a three pole main switch and a single neutral bar for all the cirucits

I do like this, but maybe a 4 pole not 3 pole

 

[Andy™]

I'm a Qs with a housing association,I replaced 2 old Consumer Unit with a new fusebox 21 way which I added another main switch for the off peak,it has 2 lines and 2 neutrals but only 1 neutral bar, my concerning is operating the off peak main switch will make the neutral bar live after midnight, should I run another conductor bar or connect the 3 storage heater neutrals into the bottom of the off peak main switch?

you need to go back and start again with a suitable board designed for this, or 2 individual boards. they way you are going will not end well

 

[SPECIAL LOCATION]

I'm a Qs with a housing association,I replaced 2 old Consumer Unit with a new fusebox 21 way which I added another main switch for the off peak,it has 2 lines and 2 neutrals but only 1 neutral bar, my concerning is operating the off peak main switch will make the neutral bar live after midnight, should I run another conductor bar or connect the 3 storage heater neutrals into the bottom of the off peak main switch?

So you designed and installed this new arrangement...
But the thought never crossed you mind that previously you had 2x Main Switches and 2x Neutral bars?

Why didn't you consider using an amended split-load type board with dual neutral bars already fitted, and a second main switch in place of where the double pole RCD went?

Basically you have purchased an installed the wrong product, which now either needs butchering or replacing with a more appropriate product..
Bit of a rookie error for a QS IMHO.

 

[Fleeting]

Mmm what do I need. Let me think, I've got it a dual tariff consumer unit.

 

[newfutile]

it was an emergency job and this was the only board i could get a short notice,i have never installed a dual tariff board.
we install very little usually here (we often struggle to find installs for NICEIC).
my main job here is inspection and testing and auditing contractors.

 

[UNG]

I'm sure there is some information missing here

it was an emergency job and this was the only board i could get a short notice,i have never installed a dual tariff board.
we install very little usually here (we often struggle to find installs for NICEIC).

How did swapping 2 CU's into one become an emergency job that you couldn't bring a contractor in who may have been better equipped

my main job here is inspection and testing and auditing contractors.

If you are carrying out inspections and auditing contractors I would have thought you would have come across Dual Tariff boards as I doubt this is the only Dual Tariff property in the housing associations portfolio

I'm a Qs with a housing association,I replaced 2 old Consumer Unit with a new fusebox 21 way which I added another main switch for the off peak,it has 2 lines and 2 neutrals but only 1 neutral bar, my concerning is operating the off peak main switch will make the neutral bar live after midnight, should I run another conductor bar or connect the 3 storage heater neutrals into the bottom of the off peak main switch?

Looking at the Fusebox website the 21 way CU is a double bank consumer unit with the same footprint as the dual tariff option and both have the same drawing so I would assume there is the option to fit additional neutral and earth bars

For an emergency repair if a dual tariff CU was not available the options would be as above if the supplier didn't have the additional neutral bar available separately I would have just purcased another CU carcass and use the parts needed from that (easy enough to order the bits to make up the unit at leisure) to configure the 21 way CU as a dual tariff unit
The other option would have been to use 2 CU's as the original installation setup

Working under pressure can be difficult and not sure what you consider an emergency job in this case but time constrained reactive maintenance can be difficult especially if you don't have a good relationship with suppliers, in an emergency call out situation a temporary repair for me is always the first option, if an emergency repair needs a board swap especially on an installation that is / should be regularly inspected then something needs reviewing

 

[binky]

it was an emergency job and this was the only board i could get a short notice,i have never installed a dual tariff board.
we install very little usually here (we often struggle to find installs for NICEIC).
my main job here is inspection and testing and auditing contractors.

Ok, emergency over, the board needs correcting . NICEIC are not the only people who register electricians. I left them years ago for NAPIT due to costs. In fact I would say most sparkies are registered elsewhere these days.

 

[Andy™]

we often struggle to find installs for NICEIC).

im not surprised. there is more than just NICEIC so by stating NICEIC only you've dismissed a large amount of contractors