What kind of incoming electrical connections are these?

[ban-all-sheds]

"
Only £94.50
"
FFS.

It can be done for a fraction of that if you are happy for one shower to take priority over the other. As far as I can see that thing is so primitive that turning on shower #1 while #2 is running will kill #2.

 

[bubachuba]

"
Only £94.50
"
FFS.

It can be done for a fraction of that if you are happy for one shower to take priority over the other. As far as I can see that thing is so primitive that turning on shower #1 while #2 is running will kill #2.

no, if say the upstairs one is running and someone attempts to turn the ground floor one on, this device will not allow that until the upstairs one has been turned off.

 

[newconnection]

Doesn't look very dormant to me the meter is still on its showing 44 units used and doesn't look old enough to have gone round the clock. You cant have it ripped out if you have only just have it put in your supplier would think you were nuts.

I didn't say it's dormant at present.
I've had 5 separate supplies put in so this is surplus to requirements for now (it's the original setup). I just thought it may be worth keeping in case future dwellings are created and if this is some sort of expensive three phase which cost a boat load to have installed again.

 

[newconnection]

The house has 2 metres at the moment but I would like to consolidate into one. It will be split over 3 floors and have at least 2 electric showers. Can someone tell me by looking at the picture if the current incoming supply could cope with that?

A single phase supply can do 1 electric shower. Perhaps 2 if there were no other electrical heating or cooking appliances in use, meaning it was all gas. However if gas is available that should be used for water heating and showers as it's 4x cheaper than electricity.

A 3 phase supply can do several electric showers, but that also means additional installation costs as you will require a 3 phase DB installing rather than a domestic consumer unit. This assumes that what appears to be a 3 phase supply in the picture actually is.
It's still total madness to consider multiple electric showers as they cost a fortune to operate and their performance is pathetic.

2 or more showers also requires that the water supply has suitable pressure and flow at the times that the showers are likely to be used.

Thanks.

The plan is to have 4 or 5 showers so I wanted 1 or 2 to be electric in case the boiler ever fails.

Assuming the supply is 3 phase, is there any benefit to keeping it as such or reducing it to single phase?

 

[PBC_1966]

no, if say the upstairs one is running and someone attempts to turn the ground floor one on, this device will not allow that until the upstairs one has been turned off.

And vice versa? In other words, is it a two-way lockout or does one always take priority over the other?

No. 1

The house has 2 metres at the moment but I would like to consolidate into one. It will be split over 3 floors and have at least 2 electric showers. Can someone tell me by looking at the picture if the current incoming supply could cope with that?

At least two? Maybe more? You have to realize that the typical ~9.5kW electric shower will pull almost 40 amps from the supply the whole time it's running, so it's a substantial proportion of the total power available on the typical supply. If you're running two such showers simultaneously, plus electric cooking, electric space heating etc. you'll easily reach the limit of even the standard 100A single-phase supply.

If you have two or three phases available already (as appears to be the case), then distributing the load of the showers across the phases would certainly be beneficial. But in order to say if the existing supply cable would be adequate, we would need to know what else you intend running (especially in the way of electric heating of any sort - cooking, space, water), and you would need to check with your supplier what options are available.

No. 2

The DNO has installed a new ground cable and 7 way panel for 5 flats.

Ah, so the DNO has already provided 5 separate meters for the new flats. With you now.

I've had 5 separate supplies put in so this is surplus to requirements for now (it's the original setup). I just thought it may be worth keeping in case future dwellings are created and if this is some sort of expensive three phase which cost a boat load to have installed again.

These days, even a basic single-phase supply is likely to cost a boat load to have installed, or for that matter to have removed. Once you've finished with this supply, your supplier will remove all the metering equipment and you'll just be left with the supply cable coming up to the service cut-out.

So long as it's not in your way, you might as well just leave it in place where it is in case of any future changes and to save a lot of money. You could box around it if you want to hide it away, but don't completely seal it up so that it can't be accessed easily in the future, e.g. make a false cupboard, or a deep cupboard with an easily removable access panel, etc.

 

[PBC_1966]

Assuming the supply is 3 phase, is there any benefit to keeping it as such or reducing it to single phase?

First, whatever you ask for from your supplier, the service cable won't be changed, unless it's not of sufficient capacity and needs to be replaced. Assuming that it is 3-phase service, if you order single-phase service of whatever rating and the cable is already adequate, your supplier will just connect a single-phase meter to one phase, leaving the other two unused.

So much depends upon your total demand and the existing supply cable. If the latter is already capable of carrying 100A and a single-phase 100A supply is enough for your demand, then that would almost certainly be the cheapest route, for reasons of 3-phase distribution boards costing more etc. already mentioned.

But if you can't get the demand you require as a single-phase supply on the existing cable, then having the DNO run a new single-phase supply cable brings you back to the "boat load of cash" situation again, and a 3-phase service may well be cheaper in the long run as even though you might spend a little more on switchgear, it will be more than compensated for by not having to pay the DNO for a new supply cable.

Again, it's hard to be more precise without knowing a lot more about the intended total load.

 

[flameport]

The plan is to have 4 or 5 showers so I wanted 1 or 2 to be electric in case the boiler ever fails.

If the boiler breaks you switch on the electric immersion heater(s) in the hot water cylinder(s).

 

[JohnD]

is this an old building you are thinking of converting into an HMO?

 

[ban-all-sheds]

If the boiler breaks you switch on the electric immersion heater(s) in the hot water cylinder(s).

If there are any.

And even when there are, it is pretty much unheard of for them to be large enough to contain enough hot water for a household-full of showers in quick succession, or for the IH to be powerful enough to heat the water anywhere near quickly enough.

 

[JohnD]

Anyone who has a hot-water cylinder and chooses not to have at least one immersion heater in it is a buffoon.

As an emergency backup, it makes the difference between "being able to have brief showers and wash up in comfort" and "having no hot water."

Every boiler will be out of action sometimes.

 

[bubachuba]

no, if say the upstairs one is running and someone attempts to turn the ground floor one on, this device will not allow that until the upstairs one has been turned off.
And vice versa? In other words, is it a two-way lockout or does one always take priority over the other?

yes, from memory there is no preference. the first device powered on wins!

 

[newconnection]

The house will be over 3 floors so will have the usual electrical sockets and lights with maybe a couple of external security lights. It will be heated by gas central heating. I was intending to have a 300 or 500 L unvented cylinder with a hot water loop.

As mentioned, I think 1 or 2 electric showers as a back-up would be useful. I will likely need around 5 showers in total.

Reading through the responses, I think 100A should be enough and if I need to reduce down to 1 electric shower for that, so be it. The only possible addition in future might be an electric car charging point but that is just 'future thinking'.

If I have understood correctly, IF there is a three phase supply at the moment, if I want to take 'advantage' of that, I'd need a three phase meter from the electricity supplier? I'd also need a three phase consumer unit?

And the only time I'd need the three phase is if I have a requirement > 100A?

 

[ban-all-sheds]

Would you want to use it as a 3-phase supply, or as 3 single-phase ones? There's not much call for the former for domestic use in the UK....

 

[PBC_1966]

If I have understood correctly, IF there is a three phase supply at the moment, if I want to take 'advantage' of that, I'd need a three phase meter from the electricity supplier?

Yes.

I'd also need a three phase consumer unit?

Or you would need three single-phase ones, since as has been pointed out already, you're not likely to actually want to use 3-phase power for anything in a domestic environment, it would just be a case of distributing your single-phase loads across the phases.

And the only time I'd need the three phase is if I have a requirement > 100A?

If the existing supply is capable of supporting a 100A single-phase service, which you would have to ascertain from the supplier/DNO. If you needed 100A but the current supply cable is only good for 80A, then you would probably be better off opting for 3-phase on this existing supply rather than having the DNO install a new 100A single-phase supply. Any time you get involved with the DNO running in a new service cable, it will become expensive very quickly. A 3-phase board or three single-phase units would almost certainly be cheaper than having the DNO run a new cable.

 

[newconnection]

Would you want to use it as a 3-phase supply, or as 3 single-phase ones? There's not much call for the former for domestic use in the UK....

To be honest, I don't know. I am just trying to understand the options at the moment.

What are the advantages/disadvantages of a 3-phase versus 3 single phases?