3 phase conundrum

[PatsPatter]

The property we are renovating has a 3 phase-fed, off peak, ducted, warm air heating system - and it works surprisingly well. It has a single phase immersion on the off peak as well and a normal tariff daytime top up.
That's the easy bit.
The house is a being extended and completely rewired. (largish three bedroom dormer, large garage/loft, workshop, outbuildings, etc.
I'm also going to install my old 3 phase machine tools in a new workshop.
The original domestic (6 way) consumer unit was an ancient Wylex with wire fuses and fed from one phase.
The electrician has done most of the new domestic wiring and replaced the consumer unit with an 13 way split load unit - but still fed by one phase.
The supply for the heater and immersion is still on an ancient MEM ceramic/wire isolator - from all 3 phases - no RCBO/RCCD protection whatsoever and is about to be replaced. He has produced - and I've paid for - a large (expensive) Schneider Acti9 Isobar distribution cabinet, with 12 three phase outgoing ways - as in 36 terminals.
Trouble is………. he's baled out of it.
My questions are:
would it be better with the 'domestic' side of it split between the phases (at least two of them)
where is the best place to protect this lot?
how is the wiring for my new workshop and 3 phase machinery best laid out?

Doubtless there will be other questions as well.

I want to understand what any future electrician should be doing. Rewiring the rewiring is not what I'd consider a useful way of disposing of my limited funds.

Given time and research, I'm confident I could do it - but it will still need to be signed off.
Pat'sPatter
ps I'd put a photo up if you're all certain no one will have nightmares…………….

 

[securespark]

No. A pic would help.

 

[Lectrician]

Bailed out?

Find another spark.

It ain't diy.

 

[ericmark]

There is a problem using three phase with domestic, where a system is under the control of ordinary persons then we need to use type tested distribution units called consumer units. These have normally a maximum current rating of 100 amp and are single phase, domestic electricians are normally members of a scheme which requires them to follow BS7671 and to deviate they would need permission. So it is possible that the scheme provider will direct them as to what three phase panels they will accept it is really a can of worms.



The three phase system should be balanced and theory would say the house should have a distribution unit which supplies items so in the main the supply would be balanced, but since you have to use a consumer unit this can’t be done. So all other buildings, will need to have the phase used in the house, arranged so that phase has the lightest load.



The alternative was is not to use a scheme member electrician but go through the LABC who do not need to follow BS7671. Although doing that means you have no idea of the skills of the electrician.



So if I was not skilled I would select a firm of electricians rather than a sole trader, the firm will likely have a mixture of electricians including ones who normally use three phase, and the firm is likely to be able to get their scheme provider to wave the restriction of BS7671 in some way, likely they will agree to be your electrician and then they become the responsible person not you.



I have worked in many small factories with three phase, and most of the machines take the three phase and turn it into DC then back into AC to power the motors so in real terms they had no need for three phase with inverter drives on their motors.



Many farms have a selected electrician who is considered as the responsible person plus the three phase goes into some out building and the house if fed from that, this means only the house comes under Part P the other buildings do not. Yes stupid rules but we did not make them.



So look for a firm which does both domestic and commercial and get them to do the job, and they will decide what distribution unit to use, I know I had units I liked and units I hated, there was one large manufacture who made a distribution unit where to switch off RCBO’s went in one direction and MCB’s went in the other direction which put me off that make for life. But now so many of the makes I knew are under the same name and I am completely out of touch as to which are good and which are bad.

 

[PatsPatter]

No. A pic would help.

Here yer go

The meter and all the terminal blocks are new, fitted a couple of months by eon when they replaced the old meter. That was done after the new consumer unit, etc was fitted.
The MEM isolator is the one described and switches the off peak units.
The incomer fuses are all 60 amp, not 100
Pat'sPatter

 

[deadshort]

Here yer goView attachment 106067

Your lucky he bailed ! Rough as a badgers, perhaps he was out of his depth ?

DS

 

[PatsPatter]

Your lucky he bailed ! Rough as a badgers, perhaps he was out of his depth ?

DS

My thoughts exactly. Both options applicable.

 

[Lectrician]

Plastic consumer unit? No pride taken in the install at all.

 

[PatsPatter]

There is a problem using three phase with domestic, where a system is under the control of ordinary persons then we need to use type tested distribution units called consumer units. These have normally a maximum current rating of 100 amp and are single phase, domestic electricians are normally members of a scheme which requires them to follow BS7671 and to deviate they would need permission. So it is possible that the scheme provider will direct them as to what three phase panels they will accept it is really a can of worms.



The three phase system should be balanced and theory would say the house should have a distribution unit which supplies items so in the main the supply would be balanced, but since you have to use a consumer unit this can’t be done. So all other buildings, will need to have the phase used in the house, arranged so that phase has the lightest load.



The alternative was is not to use a scheme member electrician but go through the LABC who do not need to follow BS7671. Although doing that means you have no idea of the skills of the electrician.



So if I was not skilled I would select a firm of electricians rather than a sole trader, the firm will likely have a mixture of electricians including ones who normally use three phase, and the firm is likely to be able to get their scheme provider to wave the restriction of BS7671 in some way, likely they will agree to be your electrician and then they become the responsible person not you.



I have worked in many small factories with three phase, and most of the machines take the three phase and turn it into DC then back into AC to power the motors so in real terms they had no need for three phase with inverter drives on their motors.



Many farms have a selected electrician who is considered as the responsible person plus the three phase goes into some out building and the house if fed from that, this means only the house comes under Part P the other buildings do not. Yes stupid rules but we did not make them.



So look for a firm which does both domestic and commercial and get them to do the job, and they will decide what distribution unit to use, I know I had units I liked and units I hated, there was one large manufacture who made a distribution unit where to switch off RCBO’s went in one direction and MCB’s went in the other direction which put me off that make for life. But now so many of the makes I knew are under the same name and I am completely out of touch as to which are good and which are bad.

Thanks for the advice ericmark. The 'farm electrician' option sounds about the best. I'm surrounded by farms.
The 3 phase panel is a good one, I've paid (quite a lot) for it, it's well OTT for the job but that never hurt.
I'm not without experience, or knowledge, having run many three phase motors off single phase and taught myself how to build automatic start phase converters.
I must have built about 20 over the years, mostly tailored to individual machines. The tricky bit was always getting the motor to reverse - but I digress!
Having bought a property which luckily has a 3 phase supply, I really want to make use of it for my lathe/mill/saw, etc - but not at any cost.
This is the last house I will ever renovate and it's my retirement entertainment. I know there are things/rules which will dictate what is possible/acceptable and as always, there's a budget. I don't want to be left with a setup decided by someone else and useless to me.
PatsPatter

 

[PatsPatter]

Plastic consumer unit? No pride taken in the install at all.

Err… aren't most of them, these days?
Ooerr, error! There not, are they. Hmm, now you mention it, it does look a bit nasty, I agree. It wasn't the sparky's fault, though.
PatsPatter

 

[Iggifer]

Err… aren't most of them, these days?
PatsPatter

Not since 1st January. They should be made of a non-combustible material (or in a non-combustible enclosure), which every manufacturer has taken to mean metal.

 

[PatsPatter]

Not since 1st January. They should be made of a non-combustible material (or in a non-combustible enclosure), which every manufacturer has taken to mean metal.

……….. in which case, it'll get changed.
Now.
Anyone want a 'heritage', one owner only, plastic consumer unit?
PatsPatter

 

[Iggifer]

What I don't understand is why everything isn't all going into the lovely Schneider 12 Way TP+N board? And why that Sector POS is still there

 

[securespark]

What's the unit with Eon & Proteus on it?

 

[Spark123]

Possibly a time switch?