Supply from mains or from tank?

[8ball]

Hi everybody and hope you didn't get to much disruption from yesterdays weather.

 

So at present I am drawing out on paper my plans for my downstairs toilet and utility room and was questioning if I can take the cold feed from the mains to supply the toilet, 2 x sinks. The reason I ask is because at present everything else in the house apart from the kitchen sink and washing machine is supplied by the tank in the loft.

 

The mains supply comes into the property at the location of the new utility room so is quite handy.

 

Thanks people ?

[8ball]

 

18 minutes ago, richi said:

That's what I did in our extension, and what I'm doing in the new utility/loo. In the latter, I'm putting in an under-sink tankless electric heater, to avoid long waits for hot water. I'm using a Stiebel Eltron system, with this heater: https://amzn.to/2xIwPIy and this tap: https://amzn.to/2NYKLbH

 

Hey Richi thanks for the reply, thats a smart set up and must admit I'm tempted as our hot water takes an age to supply the taps down stairs.

 

So there is no building regs or anything weird about going directly from mains when you already have a water tank in the loft?

 

Cheers

[Triassic]

 I’m building a new house and all the cold water taps will be fed directly off the mains. I’ve seen too many dead things in water tanks!

 

ps. Come to think of it, all my hot water will be at mains pressure via a hot water heating system, no tank in the loft.

 

 

Edited September 21, 2018 by Triassic

[Ed Davies]

Presumably those tankless heaters will need their own circuit from the CU, though? Like an immersion or cooker circuit. Or would an FCU be sufficient?

Edited September 21, 2018 by Ed Davies

[8ball]

29 minutes ago, Triassic said:

 I’m building a new house and all the cold water taps will be fed directly off the mains. I’ve seen too many dead things in water tanks!

 

ps. Come to think of it, all my hot water will be at mains pressure via a hot water heating system, no tank in the loft.

 

 

I feel exactly the same about the tank in the loft, every time I go up there to drag Christmas decorations down it sits there wrapped in its black cape all creepy and old and I don't even want to look at whats floating in it? ?

[8ball]

27 minutes ago, Ed Davies said:

Presumably those tankless heaters will need their own circuit from the CU, though? Like an immersion or cooker circuit. Or would an FCU be sufficient?

I have no idea if they need their own circuit or not but am going to look into them as whilst I have ceiling down and what not it might be worth running cables if need be.

[richi]

That one needs a dedicated supply. It's the 5.7 kW version. But there is a 3.3 kW, which I think you could put on an existing ring or radial.

 

We like the Stiebel Eltron gear. I put a similar one in the new kitchen (albeit a version you can use with any tap). The ones I linked above need to be switched via the tap itself.

[Jeremy Harris]

1 minute ago, richi said:

 But there is a 3.3 kW, which I think you could put on an existing ring or radial.

 

 

3.3 kW at the UK nominal supply voltage of 230 VAC = 14.35 A, so it can't be connected to a FCU, as they only go up to 13 A. 

 

The maximum power that can be drawn from a 13 A supply is 13 A x 230 V = 2.99 kW.  If it's a resistive load, like a heating element, then it will probably deliver more than this power, as in reality the UK mains supply voltage is still really 240 VAC.  When we harmonised with the EU, it was agreed that our nominal supply would be stated as 230 VAC, but we were allowed to have a tolerance of +10%, -6%, which conveniently allowed us to keep our 240 VAC supplies without changing anything, because they are within the allowable tolerance (minimum supply voltage is 216.2 VAC, maximum is 253 VAC).