Help with Farm/Light industry diversity

[Monchichak]

Hi There,

Moving into deeper waters & needing a little assistance with calculating maximum demand/diversity on a farm/light industrial site planning to upgrade to 3 phase, add a car repair workshop, 63A events socket & allow for future proofing.

Current single phase setup:
Diversity for lights, sockets & heaters (Not compressor or ramps) taken into account.

-2 barns rarely used, sockets & lights 33A
-1 very small domestic dwelling with ground source heat pump 53.3A
-Small carpentry workshop attached to small barn inc. water heater 23.5A
-Tinkerer garage with 40A welder socket 57A
-Auto electrician with kitchen including water heater 44.5A
-Car workshop 17A
=228A

Additions planned:

Additional unit for car garage is being built which will have
-2 x small offices + workshop lights & sockets 38A
-3 x car ramps 16A
-1 x compressor 32A
-2 x water heaters 13A
-heating for offices 37A

63A events socket which will be rarely used
=199A

Allowance for 2 extra light industrial units/car workshops for future proofing.
=100A

I'm having difficulty calculating the required kVA for the 3 phase supply - call it lack of experience. Simply adding up the demand gives me 527A which would be 175A per phase requiring 3 phase 120kVA supply without PFC taken into acc. which I think it excessive.

Any advice on calculating the ideal supply would be much appreciated.

Chris

 

[telectrix]

100 -120A per phase should be more than adequate. balancing the phases is critical.

 

[Monchichak]

Thanks Telectrix

80kVA 3 phase works out at 115A per phase which seems good to me, I'll keep that as a guide & see where the price breaks are etc for the upgrade.

Regards
Chris

 

[PEG]

Hi,that is quite an upgrade,have you enquired as to what is available?

Some of your anticipated loads are actual,some OCPD or socket ratings. You need to estimate with actual loads in mind,not just add up a row of DB sticker figures

Your customer may need to have a firmer idea of the requirements re:future proofing,as this may add considerably,to the cost of achieving their current plans.

 

[Monchichak]

Morning PEG,

An 80kVA upgrade is available although at considerable cost & a 3 phase conversation is definitely required for the new car garage.

Actual loads - this is where I ran into difficulties because the system usage varies so much, the actual load is minimal but the potential load is huge which I've tried to take into account following the diversity guidance. I can see areas where I could reduce the figures but I'm aware with the current setup & a slight change of use (barn to workshop conversion) a few heaters added then the demand rapidly increases.

The events supply is an additional buffer but maybe required on occasion.

Re: Future proofing. My customer is definitely keen to have some headroom for additions to the supply & there is plenty of space/opportunity for this.

It's a difficult decision to make but I appreciate your thoughts.

Chris