Control panel feeder cable sizing

[Lc1]

Hi,
We have a control panel that has a vsd, plc and motor anti condensation heater. For a preliminary cable calculation for the control panel feeder cable and its associated protection, would we just total up the individual loads to arrive at an approximation and use this to size the feeder cable ?

Thanks

 

[Spoon]

Hi,
We have a control panel that has a vsd, plc and motor anti condensation heater. For a preliminary cable calculation for the control panel feeder cable and its associated protection, would we just total up the individual loads to arrive at an approximation and use this to size the feeder cable ?

Thanks

Doing what you said above you would most prob get a cable that is oversized. All depends on the panel.... Not that oversized cables would be bad.

Give is the equipment figures and then tell us what you get.

 

[Darkwood]

If you are unfamiliar with the load requirements of the machine then discuss with the manufacturer, alternatively refer to the plate and/or information supplied with the machine as this usually specifies what KW rating or ampage it is and then size accordingly.
The only time you need to consider other factors is like high inertia loads where start up currents may remain higher for longer and thus impact on supply cable sizing.

 

[Lc1]

Hi,
We have 43.5A for the drive and at this stage I have assumed 10% for the remainder.
So fuse size chosen is 50A and 10mm2 cable based on the installation details.

 

[Darkwood]

You need to check the requirements of the drive, the drive manual usually expresses a minimum fusing to ensure you don't get nuisance tripping, if the drives pulls 44amps then it may recommend a 50 or 63rated.
Experience is good to have here because of the many variables, I'm guessing the drive is either 1ph - 3ph 11kw or 3ph-3ph 22kw given the values you gave.

I would on the limited info provided fit 63amp fusing and design the cable for 50amps load assuming your 10% covers all the other loads and max demand of the machine. Note dependent on installation conditions you may need to add additional earthing if you undersize the cable rating to the mcb/fuse rating.

 

[Deuce]

Hi,
We have 43.5A for the drive and at this stage I have assumed 10% for the remainder.
So fuse size chosen is 50A and 10mm2 cable based on the installation details.

What sort of ambient? I take it this is in a conduit?

By instinct since it's fused down anyway, I would go for 16mm2. Unless perhaps it was always likely to be relatively cool in the space and the box I was feeding into was particularly tight/awkward.

 

[Bobster]

From your terminology, are you based it the US?

 

[Pete999]

Hi,
We have a control panel that has a vsd, plc and motor anti condensation heater. For a preliminary cable calculation for the control panel feeder cable and its associated protection, would we just total up the individual loads to arrive at an approximation and use this to size the feeder cable ?

Thanks

Voltage? Distance from POS? Number of Phases?

 

[Lc1]

Hi,
Voltage is 400v 3 phase 50hz Distance is approximately 30m.

Thanks

 

[Darkwood]

@Lc1

Your profile is still down as Trainee, are you still training or been some years ago are you now on the tools independent or with a company?

 

[Lc1]

Still training. Trying to further my knowledge by getting involved in as much as possible.

 

[Deuce]

Hi,
Voltage is 400v 3 phase 50hz Distance is approximately 30m.

Thanks

With the known current requirement being around 50a, you're potentially approaching the limit of 10mm2, especially if there is the potential for it get warm. Seems like it's easiest to just fit a 63a isolator socket. Run a 16mm2 H07 from that. You can get the sockets with module space if you wanted to step down to 50a MCB and/or also RCD.

Leaves capacity for future expansions or replacement, and it's a fairly standard industrial solution. I'm pretty sure no-one would question it.

 

[Pete999]

Voltage? Distance from POS? Number of Phases?

Cable Sizing Calculator - myElectrical.com - https://myelectrical.com/tools/cable-sizing-calculator

 

[MDJ]

I have to congratulate the guys here, how they managed to give the OP an answer from the info in the OP is beyond me. The guys on here are very helpful, fair play.

 

[Deuce]

I have to congratulate the guys here, how they managed to give the OP an answer from the info in the OP is beyond me. The guys on here are very helpful, fair play.

Not sure the answer exists just yet. 30m and we don't even know the ambient temperature or how the cable is to be run.

Although I'd be surprised if the final conclusion was anything less than 16mm2. 10mm seems a bit stingy, especially given the length.