RE-LOCATE / UPGRADE 3 PHASE CONSUMER UNIT

[teevee]

I need to relocate the 3 phase consumer unit in my new house as 1) its underneath the stairs and you have to crawl 3 meters on hands and knees to get to it and 2) its a Square D Load center with 18 ways of which 4 are doubled up. I also need to upgrade by installing an RCBO.

 

It seems to me there are two ways of doing this,

 

1. buy a new Square D 3 phase 63 amp 24 way load center along with a new 3 phase 63 amp Safe T Cut RCBO and install both on a convenient wall about 3 meters from the existing load center.

 

2. buy 3 new 63 amp (50 amp ?) 8 or 10 way single phase consumer units and use one for each phase, installed together on a convenient wall about 3 meters from the existing load center. I was at Global House this morning and single phase 63 amp consumer units with RCBO and 10 MCBs (16, 24 and 32amps) are readily available. 

 

 I do not want to re-locate the existing Square D load center as that will mean at least 2 days without power whereas installing a new one will mean a few hours without power. Also, I’ll keep the Main breaker in the existing load center so you can isolate the house with one breaker. 

 

The cost of the 63 amp single phase consumer units ranges from 2,500 to 4,000 baht - my choice would be a Siemens unit as opposed to other “unknown to me” brands like Racer, CEO etc even though they appear to be OK. 

 

the cost will be about the same for either option but I think the second option will be the is most effective with three separate RCBOs so if one trips I still have the other two phases working. I will need to “balance” the three separate phases but thats easy enough to do and really involves no extra work.

 

Any comments and/or advice appreciated . .. 

 

 

 

[bankruatsteve]

You are probably best to go with 3 single phase units.  If you are likely to want gadgets, a Din-rail box is the way to go.  

[Crossy]

I too would treat it as 3 single-phase supplies with DIN mount units.

 

At the supply levels we are talking here there's no real need to get perfect (or even good) balance between phases.

 

[RichCor]

5 hours ago, teevee said:

the 3 phase consumer unit in my new house as 1) its underneath the stairs and you have to crawl 3 meters on hands and knees to get to it

Um, did they also install your telephone at the top of a pole?

 

 

[Metropolitian]

Before I would giving advice I would like to know a few things first:

 

• Do you have something that need 3 phase and does it has a 3phase socket/connector?
• How many floors is your house
• Are the wiring from the customer unit to the floors/rooms freely accessible ? (cabling in the wall or on the wall? Plus attic/ceiling?)

[Yellowtail]

Going with three single-phase panels would (as indicated above) make it difficult to power and three phase equipment and kind of defeats the purpose of having three phase to start with.

 

Breaking the phases up and using one on each floor I would guess it would result in a very unbalance load. 

[Crossy]

1 hour ago, Yellowtail said:

Going with three single-phase panels would (as indicated above) make it difficult to power and three phase equipment and kind of defeats the purpose of having three phase to start with.

Breaking the phases up and using one on each floor I would guess it would result in a very unbalance load. 

 

Since our OP is retaining his existing 3-phase panel he would have no more difficulty powering any potential 3-phase kit than he does now.

 

Also 3-phase RCDs open all 3 phases when they operate, killing all your power so single-phase boards are "better" in that respect too.

 

Having 3 phase allows you to distribute your supply across different phases (not necessarily by floor).

 

I sometimes wish we'd gone for 3-phase although our load isn't large. A very common failure here is the loss of one phase (it's always the one we are on) with the other phases unaffected.

 

With a distributed supply you keep 2/3 of your stuff. Of course you don't need 3 panels to do that but it does illustrate that 3-phase isn't just for 3-phase kit.

 

You can also get devices which select the "best" phase automatically for your essential equipment.

 

 

 

 

[teevee]

Thanks for the advice / comments thus far, in answer to one or two questions: 

 

There is nothing that requires a 3 phase supply and I there never will be.

The 3 phase supply came with the house so there is no “defeating” the purpose of the 3 phase supply. 

 

Overall the house is very well wired - earthed and colour coded throughout (apart from the really stupid location of the existing Load Center) and no existing wiring will be altered at all.

 

Thanks for the comments and advice, I think I’ll go with the 3 x Single Phase DIN Consumer Units (most likely Siemens) and retain the main 3 pole breaker on the existing Square D Load Center.