An odd supply...

[Lectrician]

I am doing some work at the moment which involves fitting some new switch gear at the origin of a new supply. The new supply is an upgrade to a supply which has been out grown.

It is a little bit odd, but can anyone decipher what is going on?

It is not too unusual, certainly not in parts of this area.

 

[Adam_151]

You wouldn't have posted it if it was as simple as 24/7 and E7 DBS.... so going to go with it being a 1 phase 3 wire / split phase system

Oh, and the budget being too high - merlin switchgear indeed

 

[Spark123]

5p on a 2 phase system

 

[RF Lighting]

It must be with that there single neutral conductor

 

[Steve]

wider photo please!!!

 

[AdrianUK]

Is it a 240/480 split phase service?

Adrian

 

[Lectrician]

As wide as it gets....

It is a split phase 230/460 supply. There is no three phase available, only a single pair of OH 11kv, so split phase was all that could be affordably offered.

I wanted to keep a main isolator for the installation, but am still on the fence with it TBH - the switch is only rated to 415v as are all iso's these days. I have put the phases on the outer poles, and personally think it is fine. There is a neutral link top and bottom of the iso.

The meter box is the other side of the wall from the trunking.

 

[JohnD]

- the switch is only rated to 415v as are all iso's these days.

is that a problem?

 

[Lectrician]

Personally I don't think so, and am happy with the way it is done (otherwise I wouldn't have done it).

There is a potential of 460v between the two furthest poles.

 

[Adam_151]

Be sure to note it as a deviation on your EIC

Be interesting to find out what Schneider electric have to say on the matter...

The older MEM silver handle quater turn kit sticks in my mind as being rated to 500v... wouldn't look right there anyway tho, lol

 

[RF Lighting]

Yeah, MEM Exel were definatly 500V rated, and I think MEM Glasgow were as well.

 

[ColJack]

doesn't putting the boards that high break the rules on accessibility?

 

[Steve]

What is the place?

 

[wundaboy]

Can you post a pic of the incoming supply?

Just interested in how they handle the service heads and the metering for a split-phase arrangement.

 

[Paul_C]

I see your reasoning in putting the two live poles at opposite ends of the isolator because of the 415V vs. 480V rating issue, but have you considered that it might not be a good idea not to use the marked neutral pole of the isolator for the neutral? (I'm assuming that this isolator has one section marked for neutral at one end or the other, as most do.)

The switch section identified for the neutral is generally guaranteed to make first and break last when operating the switch. If you use one of the other sections for your neutral, there's a possibility than when opening the isolator your neutral will break first, giving a brief pulse of higher voltage to one of your single-phase boards, depending upon the loads on each pole of the supply at the time.