Parallel Circuits allowed?

[ramsy]

Are there any reasons why this is not a good engineering practice other than possible code violations we discussed here?

Current may not balance if parallel length, size, or termination properties are not identical, but NEC 240.2 defines the exception for expendable labor, if trial & error makes it work.

Thanks Winne. I think 240.8 is the winner since I doubt those breakers are a single listed factory unit.

240.2 Supervised Industrial Installation, is one definition that excludes certain installations from the entire chapter, including 240.8

"conditions of maintenance" is another exclusion found throughout the NEC, starting at the enclosure with 110.70 Exception.

Safety code is selectively ignored. OSHA has injury reporting requirements if hospital admissions exceed 24 hrs, but can't prevent any carnage without a dead carcass, and someone willing to testify with proof of employer negligence.

However, administrative policy using OSHA to curb workplace corona virus may result in congress de-funding federal OSHA

 

[Elect117]

In my opinion, load balancing on the parallel fuses/breakers is an issue but how faults clear could also present as a hazard.

You would need to operate 3 breakers in order to isolate the line.

You could end up with odd fault behavior and a higher fault current than expected to be seen on a 50A breaker.

The overload mechanisms might not properly protect one of the runs depending on heat distribution of the circuits.

I would also guess they sized the EGCs to be for the 50A trip and not the 150A. That could have unintended effects like fusing of the EGC prior to clearing all 3 breakers and more likely cause fire or damage.