Spur on immersion circuit

[crash3903]

Guys

Sorry to revive an old thread.

I have fitted a pump and I now need to fit a 5amp Switched Spur for the electrics

Here is the set-up in the airing cupboard. Can I spur it off 1 or 2? It also mentions that it should have a "double pole disconnection with at least a 3mm gap". Does that mean I need a pole switch?

I'm thinking of putting the spur in-line with the immersion - Using that power supply that feeds the immersion. (Number 2 in the picture) Is that acceptable?

Thanks

 

[Taylortwocities]

I cannot see from your picture. Do you actually still have an immersion?

Strictly speaking heaters for vessels in excess of 30 litres should have their own dedicated supply.

So, is it acceptable, strictly speaking no but it is done, a lot as the immersion circuit is not used much. What is the immersion circuit fused at? 16 amps? The immersion will pull 13A, your boiler is rated at 3A (that's already connected to that circuit) plus 5A for you pump - what do you think? 13+3+5 is that more than the fuse value?

PS. The immersion is a radial so the term 'spur' does not apply. (please see a very long thread re this a few weeks ago - dont want to open old wounds )

PPS. Does the pump's manufacturer stae an RCD must be fitted? Is there one?

 

[crash3903]

Ahh thanks taylortwocities.

Number 2 in the picture is the immersion switch which we use for hot water

if that is going to be overly complicated, could I spur it into a socket nearby using an fcu

The electrical connection spec can be found here on page 5

Sorry to be stupid with these questions but the electrician we normally use is unavailable and no-one is able to help for 2-3 weeks

Your not near Bedfordshire are you and want a few quid?

 

[Veglen]

crash

There is nothing in the wiring regulations to prevent you from connecting into the immersion heater circuit for this purpose (unless you are overloading the circuit of-course) although it is not really advisable. It is not a conventional circuit arrangement and by some, considered bad practice. Although others will have other views as did the person how has already connected your boiler circuit to it!

vessels in excess of 30 litres should have their own dedicated supply.

Water storage vessels in excess of 15 litres should be supplied by there own separate circuit.

Basically a spur from the final ring circuit is the way to go! The pump requires 5A protection at the FCU, 10A if your model is BP130D. If you spur from the ring at a socket outlet or use a JB you should run a 2.5mm Twin & Earth to your FCU.

RCD protection is recommended by the manufacturer for the pump however, it is not stated as a requirement!

V

 

[holmslaw]

..

 

[Veglen]

I assume we are talking central heating pump.

Sorry holmslaw, Shower pump!

V

 

[holmslaw]

..

 

[crash3903]

Thanks chaps

I have some spare 6mm twin and earth, is that ok to connect to the JB and then into the FCU, or is it going to load the switch too much?

Thanks

C

 

[Veglen]

have some spare 6mm twin and earth, is that ok to connect to the JB and then into the FCU, or is it going to load the switch too much?

How far away is the nearest ring cable? 2.5mm isn't very expensive and will be easier to work with! However, make sure your JB is rated at 30A and your earths are sleeved.

With regards to your 6mm, it's not ideal for the reasons above however if you really want to use it up, better too big than too small!

V

 

[crash3903]

Thanks again

I have found some cable that I was going to use to replace in a lamp - white round cable which is 2.5mm but not solid copper wire- what I would call strands

I have used that - Would you recommend that I use 2.5mm grey twin and earth or is this cable ok?

Thanks

C

PS I answered your hot water thread

 

[Veglen]

Cheers crash

Your comments are very much appreciated. I was going to ask but didn’t want to divert your thread!

Anyway, the 2.5mm white flex that you are using at the moment is okay for now but only as a temporary measure! My advice would be to replace the fixed part of the installation i.e. the cable from the JB to FCU with a 2.5mm flat grey Twin & Earth before making it a permanent fixture.

The flexible cable with its stranded copper cores isn’t designed to be spurred directly from a ring final circuit to supply FCUs and the like. The mechanical protection and other factors aren’t the same! Besides, it will probably be pulled on a future PIR and that old comment “those bl**dy DIYers have been at it again” will be shouted!

Thanks again.

V

PS. I will be getting to work on mine in the next few weeks! DIY eh!

 

[crash3903]

thanks matey - will get some and replace tomorrow

till then I hope my new cu is working correctly - give me some water and copper any day