Isolator Ratings

[keithc]

We are getting some electrical cabinets delivered from America. They are supplying 4 cabinets with 1600A CB's, how do I work out what size CB I need to feed them from our supply tx. What calculation formula do you use, as we do have more coming in of different sizes.
Cheers,
Keithc

 

[jbartos]

Suggestions:
1. Supposing that you have more diversified sizes and variety of electrical equipment, then it may pay off to model and determine circuit breaker sizes via the following or similar software:
E.g. SKM, Inc. (DAPPER, A-FAULT, etc.), OTI, Inc. (ETAP), EDSA, etc.
These businesses have their web sites.

http://www.skm.com

http://www.etap.com

http://www.edsa.com

2. Less accurate approach is usually by hand with some estimations and approximations. Suggested reference:
Beeman D., "Industrial Power Systems Handbook," McGraw-Hill Book Co., Inc., 1st Edition, 1955
3. To provide more info, additional information is needed:
1. Load diversity
2. Motor load
3. Power factor compensation
4. Harmonics
5. Transformer nameplate data
etc.