Cooker and shower on the same circuit

I installed a new small consumer unit for a couple that were having an all electrical boiler to provide hot water for their wet system radiators' heating. I only did the work at the origin of the circuit. The boiler installers ran the cable and connected up the boiler. The old system was an oil boiler as there is not mains' gas available. I wonder what the "green" couple are thinking now, what with the energy prices ascending. They considered electric heating to be "green".

Z.

The customer has PV panels on both sides of the bungalow roof to maximise yields and says it works well.

As it’s a 1980’s bungalow and right on the east coast with the winds blowing in from across the North Sea I would want some more insulation in the loft.

That is the way it is going, 116 amp supplies and 53 amp circuits in two bed bungalows, but many electricians have not grasped what it involves.

But with little winter sun and at night the solar panels will be of little use. The hot water will only store heat for a short time. It sounds very costly to run to me.

Z.

Sparkingchip said:

the supply is 116 amps

That seems remarkably precise.

the supply is 116 amps

That seems remarkably precise.

Presumably nominal - 100A DNO supply plus 16A local generation (G98 limit of 16A/phase).

  - Andy.

It's probably OK if cropped so that the location is not obvious - so no personal photos in the background etc. The customer will not recognize the inside, having never opened it, and we will not see the outside...  need to know and all that. As this was presumably done by a scheme member as notifiable works, or at least existing mistakes were not spotted when the CU was changed, it does make you wonder how much value  the schemes and registrations actually add . And if they had an updated OSG, would they actually  bother to read it ?

Mike.

Wouldn't that be 16 Amps from the solar panels and the rest made up from the grid on a sunny day? At full consumption X Amps plus 16 Amps. The 16 Amps varying with cloud cover and evening light  production.

Z.

AJJewsbury said:

the supply is 116 amps

That seems remarkably precise.

Presumably nominal - 100A DNO supply plus 16A local generation (G98 limit of 16A/phase).

Yes, of course.

So will the installation ever draw 116 A? and if so, how does the 100 A main switch cope?

So will the installation ever draw 116 A? and if so, how does the 100 A main switch cope?

As far as overload protection is concerned, it is able to. That's where the new extra bit of 551.7.2 comes into play.

In more practical point of view, if the 16A comes in at the opposite end of the bus-bar from the main switch, then neither the main switch or bus-bar at any point will have to carry over 100A, In theory there's still a problem with the additional heating from the thermal elements of MCBs etc, - 116 amps worth in an enclosure designed for 100 amps worth - but given the Irish use DP MCBs as their incomers in what otherwise looks like a very similar setup to our CUs I'm not yet convinced there's a practical problem,

Of course, someone suggested CUs could be designed with a general 116A rather than 100A rating a few years ago,,,,

   - Andy,

I;m sure if it becomes a thing, stick on "16" s will be available to cover the "00"

Mean while most 100A fuses can pass 116A all day anyway.

Mike.