UK 3 phase sub board addition

[Dave123]

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Hi

Looking at a job currently adding a 3 phase solar installation but the distribution board is full obviously a new board is the best option but if the customer isn't interested in this what do people usually do? Add a small 3 phase board and use Henley blocks, I've never seen this done but I don't do much 3 phase work.

Any better options?

cheers

 

[davesparks]

What size installation are we talking about here?
Is it just a small 100A supply with tails directly feeding a single DB or is it a big installation with a busbar you can tap off for a new feed?

How many new circuits are you installing?
If its just one circuit and there's a busbar available then you could add a switchfuse to it for the new circuit.

Another option is to fit a second DB next to the existing one and move an existing circuit (or 3) into it to free up a way to feed the new DB from that.

 

[Dave123]

What size installation are we talking about here?
Is it just a small 100A supply with tails directly feeding a single DB or is it a big installation with a busbar you can tap off for a new feed?

How many new circuits are you installing?
If its just one circuit and there's a busbar available then you could add a switchfuse to it for the new circuit.

Another option is to fit a second DB next to the existing one and move an existing circuit (or 3) into it to free up a way to feed the new DB from that.

Its a small 100a 3 phase installation. Your last option could work well, add a small single phase board and move some of the lighting over to that. This would allow me to add one 3 phase mcb for my inverter.

cheers

 

[davesparks]

Its a small 100a 3 phase installation. Your last option could work well, add a small single phase board and move some of the lighting over to that. This would allow me to add one 3 phase mcb for my inverter.

cheers

Do the next person a favour and put a 3 phase board in so theres a few 3 phase ways spare for future expansion.


And I know this is obvious but try to use the same brand of DB as the existing.

 

[Dave123]

Do the next person a favour and put a 3 phase board in so theres a few 3 phase ways spare for future expansion.


And I know this is obvious but try to use the same brand of DB as the existing.

That’s the preferred option but I’m not sure the customer will go for that.

Cheers

 

[pc1966]

What make/age is the existing board?

A few like Hager offer 'neutral links' which are dummy MCB with just a link and they can be used to extend the busbar of the main board to a new one so no additional main switch needed and no selectivity issues of MCB feeding MCB. Obviously you have to be within overall current limits, etc, and as no final circuit protection on those linking cables they need to be double-sheathed (like tails) or ideally just box-box via trunking or a 32mm or 50mm bush and locknut physically linking the two DB together.

 

[James]

That’s the preferred option but I’m not sure the customer will go for that.

Cheers

So they are adding quite a lot of panels, a 3 phase solar inverter and are going to turn down 2K to put a decent board in and install it properly?

put in the quote for doing the job you feel should be done.
if they grumble, then you can say
it can be done on the cheep like this but i wouldn't recommend it.

 

[Dave123]

So they are adding quite a lot of panels, a 3 phase solar inverter and are going to turn down 2K to put a decent board in and install it properly?

put in the quote for doing the job you feel should be done.
if they grumble, then you can say
it can be done on the cheep like this but i wouldn't recommend it.

I agree but often people aren't keen on a new board as that's not what they have asked for hence lots of domestic installs have a separate small board for the Solar. I was just wondering what people often in that situation.

 

[davesparks]

I agree but often people aren't keen on a new board as that's not what they have asked for hence lots of domestic installs have a separate small board for the Solar.

Is that the reason? Or is it because of some solar installers who only care about doing the quickest, cheapest job and getting on to the next one?

 

[Dave123]

Is that the reason? Or is it because of some solar installers who only care about doing the quickest, cheapest job and getting on to the next one?

Funny how views differ most people I know regard it as best practice to keep solar in a separate board and using the existing board is a Last resort.

I always want to do a decent job, if you add a full board change, which to do properly is a full day to every job you wouldn’t get the jobs.