Cable for Salamander Shower pump

[Hylthom]

Hello

I need to install a Shower Pump in the 1st Floor bathroom and run it from a 6A MCB where the CU is located under the stairs. 

It is the Open-Vent system and the Immersion Heater is in a cupboard next to the bath. The Heater have the correct Immersion cable. In checking out the correction factors I feel 1.5mm T&E will not be sufficient. 

I am therefore looking at BSEN 50525-2-11 1.0mm 3 core Flex (3093Y), to run from CU and to link to the pump via a switched FCU. The total cable length will probably be about 7 or 8 metres.

All help and, or, alternative suggestion much appreciated. Thank you.

 

[Sharpend]

What correction factors have you applied that allows a 1.0mm cable to work but not a 1.5mm cable? 

What rating is that pump that you have? 

 

[Hylthom]

Hello Sharpend.

I only did rough calculations with correction factors, using length of (1.5mm) cable  starting at CU;  ambient temperature where cylinder is located (closed cupboard),  and length of cable exposed to that temperature within the cupboard. Whilst correction factors allow for thermal insulation, nothing is shown for cables in an environment as that encountered in the cupboard.

So knowing that the Immersion Heater is supplied by a Heat Resistant cable I felt 3093Y (Heat Resistant) would be better although it cost much more. It may be the forum feels 1.5 T&E is Okay. Thank you.

 

[Sidney]

What is the minimum size cable required by BS7671 for the type of circuit you're installing?

 

[steptoe]

There would be very few cases where 1.0mm could carry more current than 1.5mm , and it would be a pretty specialised 1.0mm to do that.

Russ Andrews probably sells that type of cable,  msl1:

 

[Evans Electric]

Hylthom    you need to tell us the rating of the shower pump ...I'd guess its around 3 amps .  Also you are getting mixed up with your cable sizes  ....1.00mm  is  SMALLER than 1.5mm  .

However   without seeing the job I'd say  1.00mm Twin/E     6242Y  will be adequate .     A shower pump  will only run for , what,  10 mins  anyway .     

You're over cooking the problem . 

 

[Andy™]

There would be very few cases where 1.0mm could carry more current than 1.5mm , and it would be a pretty specialised 1.0mm to do that.

Russ Andrews probably sells that type of cable,  msl1:

1mm pyro vs 1.5mm T&E?

Hylthom    you need to tell us the rating of the shower pump ...I'd guess its around 3 amps .  Also you are getting mixed up with your cable sizes  ....1.00mm  is  SMALLER than 1.5mm  .

However   without seeing the job I'd say  1.00mm Twin/E     6242Y  will be adequate .     A shower pump  will only run for , what,  10 mins  anyway .     

You're over cooking the problem . 

1mm T&E should be banned. hate the stuff

 

[Tony S]

1mm T&E should be banned. hate the stuff

Why?

 

[Andy™]

just one of those things i hate. same as wiring a 13a plug

 

[steptoe]

1mm pyro vs 1.5mm T&E?

specialised to most people these days

I got a job on IoM nearly 20 years ago for the very reason I could use pyro,

I even got more money than the company QS

 

[kerching]

PYRO?.........Love it

its becoming a lost art and nobody wants to pay for it unless Offshore or Chemical Industry

all petrol pump installations used to be PYRO......couldn't use CEF Pyro Glands as they were not Ex rated!

saw one the other day and it looked like it was done in SWA

 

[Evans Electric]

just one of those things i hate. same as wiring a 13a plug

Only one thing worse than wiring a 13A plug top   ....thats wiring one of those rubber Duraplug ones  and on completion  realising you didn't slide the top onto the flex first .  :facepalm:

 

[Hylthom]

Many thanks to all for your responses. As two of you mentioned, I was in fact over cooking the problem. 

I have now gone through checking things out. The boiler temperature was much too high when I first checked, hence my concern about the heating effect on the cable. And I had not yet decided which pump to get. 

1.5mm T&E will be adequate taking account of all the factors, as the pump I have chosen takes 457W, and 2A at full load.

1.0 mm 3093Y carries same current as 1.5 pvc but higher temperature.

Thanks again