Sunbed installation

[mathikrol]

Hi!
I was asked to install an additional sunbed (17kW, 3ph) in a sunbed studio.
At the moment there are already five sunbeds in place with power rating from about 13kW to 17kW. The studio has a 3ph supply (3x100A). The consumer unit is about five years old. It is 6 way. Five is already taken by the existing beds and on the sixth one there is a 63A single ph MCB that feeds a split load 10 way CU with two RCDs which powers all the lights, sockets etc.
From 3ph CU there is an existing SWA of sufficient CCC leading to the room where the new bed is to be installed (less than 10 meters long). The SWA goes through the cellar and it is clipped directly to the cellars ceiling.

What I would like to do is:

1. Connect a new sunbed to the 6th way of the 3ph CU with just a 3ph 32A type C MCB
2. Cut into a one of the phases tail with this

http://www.screwfix.com/p/2-x-5-way-dp-100a-service-connector-block-35mm/21791

and install something like that

http://www.screwfix.com/p/square-d-...se/90021#product_additional_details_container

that will feed a single ph CU

3. The SWA will feed a interlocked switch socked like one of these:

http://www.cef.co.uk/catalogue/products/1939530-32a-3p-n-e-415v-interlocked-switch-socket-ip44

and the bed will be connected to a socket

Obviously everything would be properly testes before the use to make sure that the earth path, fault current etc. are okay.

Questions

1. Is RCD required for the bed? The only suitable would be a 100mA due to the nature of the load. The sunbeds leak around 70-80mA and apparently it gets higher over time. The bed is second hand so this could be a problem. The SWA cable isn't burried at any point.

2. Am I missing anything?

 

[EFLImpudence]

As you are asking these questions and it is a commercial business, you should not do anything.

 

[Taylortwocities]

 

[ericmark]

Do your maths. Quick check it would seem you don't have the power for another bed. Clearly idea of another bed is to run at the same time as existing. I would use your clamp on rather than calculating as one is never sure how much power they really use. Likely looking at new distribution unit and upgrade supply. I may be wrong but I seem to remember consumer units are single phase and limited to 125A. As you move to a distribution unit the person in charge has to have electrical knowledge. I would say your out of your depth, time to get an industrial trained electrician to do the work.

 

[bernardgreen]

Is RCD required for the bed? The only suitable would be a 100mA due to the nature of the load.

What about the RCD being suitable to protect the customers using the sun bed ?

 

[ban-all-sheds]

I would say your out of your depth, time to get an industrial trained electrician to do the work.

I'm not convinced that he is any sort of electrician:

//www.diynot.com/diy/threads/toilet-ventilation.447818/

//www.diynot.com/diy/threads/vinyl-floor-fixing.392452/