3 X Single Phase Boards On 3 Phase Supply?

[mk1rob]

Hi guys.

Is it ok to put 3 x single phase consumer units on a 3 phase supply. One per phase out of each cut out then a henley block connecting the neutrals? Would put a 3 phase board on but theres only single phase circuits and the amount of RCBO's needed would be £££'s.

Thanks in advance!

 

[Manator]

It is possible but I fail to see how three single phase boards would cost less than a three phase board or why you would require less RCBO's.

The three phases would still need to be balanced and this is sometimes a lot harder to achieve with separated boards. Remember that not all circuits would require RCD protection.

 

[mk1rob]

Theres about 30 single phase circuits all together and all have cables buried in walls less than 50mm. Getting on for £600 just for the RCBO's at that. Was thinking 3 x Dual RCD consumer units would be cheaper and can split the circuits across RCDs so not to have 1 x RCD for the lot in a 3Ph board. Thanks

 

[SBS Dave]

Hi mk1rob,

i do single pole RCBOs @ £10.00 ea. less 10% for your qty, which is £270.00.

3 x enclosures would total about £60.00, making a job lot, including postage of about £340.00  + VAT.

the RCBOs are 10kA ssc, just in case you have a very low Ze.

If it sounds like a solution to your problem, See signature for my contact details

SBS Dave

 

[Phoenix]

It would be good if you did a three phase board that could take your RCBOs then that would result in a very neat solution for the OP

 

[Andy™]

Theres about 30 single phase circuits all together and all have cables buried in walls less than 50mm. Getting on for £600 just for the RCBO's at that. Was thinking 3 x Dual RCD consumer units would be cheaper and can split the circuits across RCDs so not to have 1 x RCD for the lot in a 3Ph board. Thanks

either its a very big house needing TP, or its a commercial installation, which doesnt always need RCD protection for cables in a wall...

 

[Manator]

either its a very big house needing TP, or its a commercial installation, which doesnt always need RCD protection for cables in a wall...

Thats what I could not get my head around Andy, why would every circuit need an RCBO ?

Even so SBS Dave's answer has me intrigued, I did not realise they where so cheap.

I do not suppose you do any Dave that fit a shnieder three phase board?? I could use them all the time.

 

[Evans Electric]

I was taking note of those too.    SDS Dave  what make are your RCBOs ?  What boards do they fit ?  

 

[steptoe]

they will fit most 'wylex' generic plus a host of others,

you could always just fit one of SBS Daves busbars into almost any board as an add on I suppose for extra circuits,

or for 'hi-integrity' before the first RCD

 

[SBS Dave]

I used to bring my 1-pole RCBOs in from China, but my Supplier also supplies TDline in the UK. I don't sell all that many, because my main product is the 2-pole Compact RCBO, so I now use the TDline. It is the same as the previous MK and Chint unit and it is the same as the current Contactum unit. To my knowledge, it is compatible with MK, Chint, CPN, BG, Curve and probably a few others. The problem with mine and other units on the market, is the lack of standardisation of terminal heights. Some can be fitted, if the busbar pins are bent slightly, but the offset required for Wylex, Hager and some other popular makes, would make them non-compatible. You can, of course, split the busbar and place the RCBOs on the end of the DIN rail.

The problem, therefore with 3-phase boards, is the fixed height busbars.

My standard RCBOs are £10.00, because that is a reasonable price for an RCBO, no matter which make it is. I have small overheads, but even with the larger overheads of the national brands, they are charging ridiculous prices for the same product.

Even my 2-pole Compact RCBOs @ £13.00 are still cheaper than most standard RCBOs on the market.

SBS Dave

 

[kme]

I can attest to the awesomeness of those mini-RCBos - you haven`t lived until you`ve tried one....................

 

[Phoenix]

Have you have ever opened one of your mini rcbos up dave? How close are things crammed in there?. There thing that concerns me as these things get smaller is if you get a component fail then with the limited clearances its more likely to flash over.

I have heard that even with standard size RCBOs, there isn't a lot of room in there and one of the major makes had an issue a few years ago with the test resister going down and then burning up with the button is pressed, and the results of this causing a flash over in another part of the device leading to a large bang and the submain being taken out.

 

[SBS Dave]

Hi Phoenix,

I have looked inside one and it is an engineering masterpiece!!

You may call it"crammed in there", but I would call it optimum use of available space.

Then it should be, as it was designed in Europe and CE certified in the UK.

I am sure that Electrium looked inside their MCBs, but they still caught fire. The RCBO problem you mention was probably not due to a product design, but a small component failure.  I am not sure if your concern about component miniaturisation is to do with engineering products in general, or my product in particular. If it is general concern, what replies did you get from the other suppliers of products you use, when you asked them the questions you asked me?

SBS Dave

 

[Phoenix]

It was more idle curiosity rather than a line of enquiry I'm chasing, prompted by when people were marvelling over the small size and it prompted me to recall an incident I read about on the IEE forums.

It wasn't that long ago that rcbos meant you had to oversize your board considerably as they took up two ways each. Mobile phones got smaller, and then all of a sudden got bigger.

The lack of a functional earth is a good step forward though, they always made the board look a mess (though many of the two module ones didn't have them either)

Don't feel that I'm trying to set out to critisise your product - I'm not, I'm just chronically cynical

Moving on...Do you have a busbar solution that permits a bank of mini-rcbos followed by a bank of MCBs?

 

[SBS Dave]

Hi Phoenix,

Maybe I am turning into a sensitive old fart, but we are who we are. Being cynical is better than not giving a sh*t.

I can assure I would not be marketing the Compacts, if I did't think they were as good the other TEF guys say they are.

Hopefully, you will try them for yourself, when a suitable job comes up.

To answer your question, you can have the busbars covering just the RCBOs and then have a separate LIVE busbar for the bank of MCBs. You can then feed the MCBs from bottom of the Main Switch, with say a 16mm or 10mm flexible link. If you ordered a board with that configuration, I would provide a neutral bar for your MCB circuit neutrals. I would even supply you with the link.

The way I work is that you design the board, give me the spec. and I build it and ship it to you, ready to fix to the wall.

However, some guys have taken stocks of RCBOs and busbars, to populate their own boards, or to upgrade existing DIN rail 16th Edition boards.

I look forward to adding you to my list of satisfied TEF customers.

SBS Dave

 

[Manator]

Dave I really do like your posts they show conviction and commitment, I think you are vindicated by the many happy and appreciative replies from those who have used your products.

As you know I was one of your first critics, but for different reasons, and you have proved myself wrong there!