losing c phase (NEED HELP)

[tmartin5150]

I have a 100 amp panel that is fed from a 100 amp switch. Tha panel feeds 2 a/c units. I keep losing C phase(fuse is blowing). Any suggestions on where to start my troubleshooting? Thx.

 

[walkerj]

Amprobe???

 

[mivey]

loose connections: look for heat (discoloration, IR scan, thermography, etc)

high impedance fault (amprobe)

intermittant fault (megger, monitor)

 

[tmartin5150]

Is it poss that one of the compressors is bad? Causing the high draw?

 

[ptonsparky]

Single or three phase units? What mca of each?

 

[mivey]

Is it poss that one of the compressors is bad? Causing the high draw?

Could be, but you will need to gather data as there are a lot of other could-bes too.

 

[tmartin5150]

Thanks for all the info. Will hav to get some more info and come back.

 

[brian john]

Fall of potential across the fuses and the FSS, from line to load.

Then as noted above.

 

[LarryFine]

Simply put, is excessive current what is causing the blowing?

 

[masterinbama]

Are you actually checking the fuses or just voltage on the load end? I had a fused disconnect once that would lose a phase. I immediately assumed blown fuse ( no voltage to ground on load end). after 6 or seven fuse changes over a 2 day period I found out that I had a loose fuse clip. When i plugged a new fuse in it would make contact for a few hours.