Change of economy 7 CU

[MickSmith5824]

Hello all

I have been asked to quote on a change of CU that I have attached photo of. I have never changed one like this that looks to me like it has a dual supply from an economy 7 meter and also a supply on the standard rates. I am aware that the actual connections from metering can vary for these and can be from 2 seperate meters or just the one. The client has also requested surge protection. As this is going to require a dual supplied CU could anybody recommend a suitable one that will serve the purpose also is there anything else I need to consider with this change. I haven't got a great deal of experience with economy heaters and not sure why at the moment they have used non isolating bs1361 fuses. Any advice would be appreciated

 

[AJshep]

Hager do one in a single stack. I believe it is called "Design 10 multi tariff".
You could then just install a hager SPD and RCBOs for outgoing circuits.

I would want to look at the job first though if I were you, at least run some tests. You don't want to quote blind then find a number of faults that will become your problem once you have changed the CU.

 

[MickSmith5824]

Hager do one in a single stack. I believe it is called "Design 10 multi tariff".
You could then just install a hager SPD and RCBOs for outgoing circuits.

I would want to look at the job first though if I were you, at least run some tests. You don't want to quote blind then find a number of faults that will become your problem once you have changed the CU.

Thank you AJ much appreciated. Just from look of existing CU looks like old install. So intend on giving an initial inspection to see what problems might lurk there.

 

[davesparks]

. I haven't got a great deal of experience with economy heaters and not sure why at the moment they have used non isolating bs1361 fuses. Any advice would be appreciated

I don't understand what you mean by non-isolating fuses, can you clarify please?

 

[MickSmith5824]

I don't understand what you mean by non-isolating fuses, can you clarify please?

Sorry I just meant they have used BS 1361 fuses for some of these circuits rather than what look like 60898 ones of the other circuits. I just wondered why this might be

 

[davesparks]

Sorry I just meant they have used BS 1361 fuses for some of these circuits rather than what look like 60898 ones of the other circuits. I just wondered why this might be

It could be that the circuits didn't meet the Zs for an MCB but they do for a fuse.
Or it could be that they just happened to have those parts on the van.
It could also be that it was all fuses to start with but someone has changed the circuits which have blown fuses in the past over to mcb for convenience of resetting.

 

[MickSmith5824]

It could be that the circuits didn't meet the Zs for an MCB but they do for a fuse.
Or it could be that they just happened to have those parts on the van.
It could also be that it was all fuses to start with but someone has changed the circuits which have blown fuses in the past over to mcb for convenience of resetting.

Thanks Dave. I'll do some quick ZS's on these circuits to check if all ok for rcbos will need

 

[ferg]

You can get dual tariff boards made to order but I would in that case just adapt a dual RCD board.

I live in the arse end of nowhere so anything special order takes an age to get here.

I would ditch the RCD's and replace with main switches and have each circuit on an RCBO.

Alternatively two small CU's with RCBO's

 

[MickSmith5824]

You can get dual tariff boards made to order but I would in that case just adapt a dual RCD board.

I live in the arse end of nowhere so anything special order takes an age to get here.

I would ditch the RCD's and replace with main switches and have each circuit on an RCBO.

Alternatively two small CU's with RCBO's

Thanks Ferg. I have considered this but have not been sure of suitability of a CU to have two main switches. Would most dual rcd CU's be able to be adapted for this? Or do you know of a specific one that I could use? Thanks

 

[ferg]

I only use Hager CU's but I can't see why others would not work in the same way.

It should be noted that some think altering a CU from it's original purpose makes you liable if there is a fault.
Sidewinder? I think was a big advocate of this point of view.

 

[MickSmith5824]

I only use Hager CU's but I can't see why others would not work in the same way.

It should be noted that some think altering a CU from it's original purpose makes you liable if there is a fault.
Sidewinder? I think was a big advocate of this point of view.

That was a consideration of mine to. But does seem like big price difference with the two option hager 10 dual tarriff with RCBO's looking around £450 at the moment. This is after I quoted initially £130 for surge protected CU.....before he let me in on its dual tariff ?

 

[ferg]

That was a consideration of mine to. But does seem like big price difference with the two option hager 10 dual tarriff with RCBO's looking around £450 at the moment. This is after I quoted initially £130 for surge protected CU.....before he let me in on its dual tariff ?

OH!

New job, new price.

He'll either get over it or not.

 

[MickSmith5824]

OH!

New job, new price.

He'll either get over it or not.

Lol yeah he'll have to ?