Chiller Feed Calcs

[SKY]

Hi All

I Have a chiller to feed power to and i'm having a play with the calcs prior to the designer.

The cable run is 60m directly clipped
I'm arriving @ 16mm CSA cable but i'm cncerned about the max start up.
Also thinking 50A C type or maybe 63A C type - but it mentions REC 80A

Electricial Data
Nominal Run Amps (A) 47.20
Maximum Start Amps (A) 202.30
Control Circuit (VAC) 24VAC
Mains Supply (V) 400/3/50
Permanent Supply (V) 230/1/50
Rec Mains Fuse (A) 80.00
Rec. Permanent Fuse (A) 4.00
Max Incoming ) Mains (mm²) 35.00
Cable Size ) Perm (mm²) 2.50
Compressor
Motor Rating (kW) 11.60
Nominal Run Amps (A) 19.80
Locked Rotor Amps (A) 175.00
Crankcase Heater Rating (W) 50.00
Type of Start Direct On Line
Condenser Fan
Motor Rating (kW) 0.60
Full Load Amps (A) 2.62

Whats the thoughts of you guys?

Ta

 

[Darkwood]

A few things...

You haven't supplied the details to allow us to confirm your cable size.
As this can be classed as a machine/motor supply then the methods to arrive at a cable rating and OCPD differ from your standard methods you may have been taught at college, your first step is to select your OCPD to suit and to know what OCPD is required then either follow manufacturers recommendations or look into the motor duty, starting arrangment etc... forget all the type B for normal loads, C for motors and D for Tx's - that was a very broad explanation and too vague for this type of calc. To give you an Idea of what I mean, you suggest a 50(c) for the 11kw motor, if you fitted this and the motor was DOL or Star/Delta starting then you can expect frequent nuiscance tripping, loss of product and a legal backlash.

If you have a designer as you seem to suggest then for this particular job, I would leave the design to them, If I was to help you out just for your curiousity then I lack too much info and I would be refering to OCPD data charts, the chiller suppliers tech' support if any , thats if I wanted to ensure cost saving on the install and not a possible oversized manufacturers guide for worse case set-up.

Given the nature of the load and the issues of a nuisance tripping would have on possible losses then I wouldn't be supplying this with an mcb at all given the motor rating and possible duty.

BS88-2 or Mccb would be my first thought here.

 

[Marvo]

Electricial Data
........
Max Incoming ) Mains (mm²) 35.00

The manufacturers are stipulating a 35mm CSA, why are you thinking about reducing this to 16mm? If anything with the length of run being 60 meters you should be upsizing to compensate.

If you install an undersized cable or OCPD for that matter, especially against the manufacturers explicit advice, you're inviting trouble. If there's any kind of warranty claim whatsoever this is the first thing they'll highlight shortly before they decline to honor their guarantee.

 

[Darkwood]

The manufacturers are stipulating a 35mm CSA, why are you thinking about reducing this to 16mm? If anything with the length of run being 60 meters you should be upsizing to compensate.

If you install an undersized cable or OCPD for that matter, especially against the manufacturers explicit advice, you're inviting trouble. If there's any kind of warranty claim whatsoever this is the first thing they'll highlight shortly before they decline to honor their guarantee.

I think this is stating the max size cable lugs the unit will accomodate, the installation itself may warrant a 50mm in certain circumstances so appropriate external switchgear would be needed in that case to allow a reduction in size to the chiller. I always seek this info out if the run is long or installation methods adverse thus warranting a larger cable, I've taken a 70mm to a 80amp load before and had to cost for switchgear at the load end to allow the cable to be sized back down.