Industrial Washer & Dryer Feeds

[chloebear]

Got a bit of a problem working this one out, maybe someone can help - I have to install 3x washers & 3x Dryers (single phase) in the same location. The only board I can take the feed off is in an adjacent building (15 / 20metres away) with enough spare ways on the current 3 phase board.
Problem is that the feed cables will need to be SWA underground between the buildings, each machine is rated at 4.8Kw even if I run 2x 10mm swa cables and split the machines 3 & 3 the maximum load on each cable if all 3 machines are running together will be in excess of 60A - over the size of the largest breaker available.

Any sugestions greatfully recieved.

 

[nickblake]

The easiest way round this would be to install a three phase sub board to the area where the machines are then wire them up in that protect it with a 63 amp TPN then install each machine on its own phase 20 amp supply

 

[Hawk81]

The easiest way round this would be to install a three phase sub board to the area where the machines are then wire them up in that protect it with a 63 amp TPN then install each machine on its own phase 20 amp supply

+1 Exactly what i would do

 

[chloebear]

Thanks for that - that would mean installing 2 sub boards? 6 machines in total - if they are all working at the same time this would be a load of 125A (28.8Kw) if I have done my sums right.

 

[malcolmsanford]

Are you saying that the tumble dryers are rated the same as the washing machines? The normal ratio in an industrial laundry is a 3 to 1 washing machines to tumble dryers. Is the area going to be 24 hours working or available.

If I were doing the job run your 2 10mm^ from the existing TPN board with a 45amp 3 pahse+N+E supply. Fit 2 smaller 3 phase boards over there 1 x washing machines 1 x Dryers. If you really wanted to you could split it as 2 washing machine 1 dryer 1 board, then 2 dryers 1 washing machine other board, it depends how easy it is to split, but as the tumble dryers do take the biggest load it may be worth splitting them.

Then run each circuit at 25amps to each machine. As per the DNO rule of thumb for light commmercial add the protection devices and multiply byt 0.6 so 75amps x 0.6 is 45 amps. Remember the machines will have thermostats and the load will not be a continous one all the time.

 

[chloebear]

Thanks for all the guidence, realy usefull. From the above by using the 0.6 factor the 125A loading would come down to 75A load - if so, then I could use a single 16mm SWA from the existing TPN board via an 80A isolator into a 3 phase board and run the locals to each of the machines.

What thinks you??????????????

 

[nickblake]

Sounds ok to me

 

[TPES]

Here comes the daft question...

4 washers
4 driers

Feeds ran in PVC trunking on surface to isolators, then flex out to each machine..

RCD required??

 

[Amp David]

I wonder how it was done in the end?

 

[TPES]

Not required to be on RCD are they if ran surface?

 

[Knobhead]

28.8KW spread over 3 phases is 40A, so where’s the problem?
Just run a 63A feed to a sub board, so long as the existing board can stand it.