Shower pump connection

[acmedone]

If you have a circuit with an immersion and CH and a shower pump on it and something goes short circuit, potentially you'll lose all three.

My daughter has grown up and left us so the world won't end.

 

[JohnW2]

In theory, two 3kW heaters could be plugged into a radial double socket...

Indeed. In fact, ten 3kW heaters could be plugged into a radial socket circuit if (quite acceptably) that circuit had five double sockets. However, it is the thankless task of the designer to use a crystal ball and make guesses about the 'likely' use of the circuit.

So long as it is only theory and the rules don't actively outlaw connecting small loads to the immersion circuit it must surely be the preferred method?

. Well, the Wiring Regulations are not law, and therefore cannot 'outlaw' anything. However, the IET's On-Site Guide, a companion publication to the Wiring Regulations proper.certainly recommends that an immersion heater has a circuit entirely to itself.

Precedence is that a cooker outlet usually has a 13A socket.

That is not a precedent. The Wiring Regs make specific provision for a single socket to be run off a cooker circuit, and specify modified diversity calculations for the circuit if auch a socket is present.

Kind Regards, John.

 

[securespark]

If you have a circuit with an immersion and CH and a shower pump on it and something goes short circuit, potentially you'll lose all three.

My daughter has grown up and left us so the world won't end.

Nevertheless, it is good practice to limit inconvenience in the event of a fault.

 

[acmedone]

Well, the Wiring Regulations are not law, and therefore cannot 'outlaw' anything. However, the IET's On-Site Guide, a companion publication to the Wiring Regulations proper.certainly recommends that an immersion heater has a circuit entirely to itself.

Excellent. In 15 years the only time the immersion heater has ever been used is when the central heating has been down for maintenance. Adding the shower pump to the immersion heater circuit it is then.

 

[JohnW2]

Excellent. In 15 years the only time the immersion heater has ever been used is when the central heating has been down for maintenance. Adding the shower pump to the immersion heater circuit it is then.

It is your prerogative, as designer, to make such design decisions. The only requirement is that the designer must be able to justify their decisions as being reasonable and safe, and it sounds that you feel you could.

Kind Regards, John.

 

[ban-all-sheds]

The OSG suggest putting immersions on their own circuit, the regs don't mention it, save for the "new" appendix concerning appliances >2kW.

And what the regulations say is to not put immersion heaters on a ring final circuit.

Nowhere do they say that you cannot design a circuit to supply an immersion heater and a shower pump.

Or an immersion heater and a shower pump and a towel rail.

Or an immersion heater and a shower pump and a towel rail and an extractor fan.

Or whatever. It's keeping the IH off the ring that matters because putting it on one tends to be a bad design (see 433.1.5).

As long as it is properly designed for the loads, you can put anything you like on a circuit (ignoring 314 for now). The point is that a ring final is not properly designed for an IH. There is no reason whatseover to say that a radial for an IH and a shower pump is not a proper design.

 

[SimonH2]

This thread has been very topical for me - my mate has been getting quotes for a new bathroom and one (only one !) has suggested putting a pump in the airing cupboard (which is not in the bathroom). There's an obvious supply there by way of the IH - but then there's a switch in the kitchen labelled "WATER HEATER", this house having been built in the days when it was still "normal" to be manually putting the hot water on in advance of a bath. So I did consider just removing the switch in the kitchen which is quite redundant now there's a "proper" DHW cylinder, Y plan system, and cylinder thermostat.

Fortunately there is a socket where I can drill through the back of the box and the wall to get an FCU off one of the RFCs.

As to location of pump, surely the consideration should not be it's height relative to the DHW cylinder, but relative to the water in the header tank ?

 

[EFLImpudence]

As to location of pump, surely the consideration should not be it's height relative to the DHW cylinder, but relative to the water in the header tank ?

True.