opinion on harmonic loads

[mike1964]

hello all, because of 310.15(B)(4)(c) i had to derate my conductors (310.15(b)(2)(a)) use larger wire, larger conduit, the whole ball of wax!!! I would just like the opinion of others in the group how they feel on this harmonic stuff. In one of my buildings i have this fancy johnson system that monitors the current on all three phases of the service (1600 amp) and neutral and have never seen more than 50 amps of unbalanced current on the neutral. This building could be the poster boy for harmonic loads.

P.S. no rework was needed i took this into account during the design portion of the project.

thanks for your opinions!!!!
mike p.

 

[roger]

Re: opinion on harmonic loads

Mike, although a real issue, I feel it is greatly over blown. I actually asked almost the same question before.

See this thread http://www.mikeholt.com/cgi-bin/codeforum/ultimatebb.cgi?ubb=get_topic;f=12;t=000033

Roger

 

[mike1964]

Re: opinion on harmonic loads

Thanks Roger, i liked the reply from charlie tuna,on your previous post

mike p.

 

[bennie]

Re: opinion on harmonic loads

I feel that a lot of neutral blow outs, and melt down, are the result of corroded connections, and not the result of harmonic current.

 

[hbendillo]

Re: opinion on harmonic loads

Mike, I hope your "Fancy Johnson" device measured True RMS current otherwise the imbalance would not show up properly. Anyway, the truth is many of the harmonic producing devices of old have been modified so that they do not produce as much harmonic current. Therefore, the problem has been greatly diminished.