If you wanna get into a really heady topic, see what happens when you put a piece of strut or gnd wire or another power wire in between parallel runs of power wire per phase on a three-phase AC system
I did a tenant fit-out in a new building where the base-building was still under construction by a different electrical contractor when we started our buildout. The building had a penthouse switchboard that was fed with 5 parallel sets. Except the other EC pulled it as 1 phase per conduit. So they had 1 conduit with 5x a-phase conductors. Another with 5x b-phase, etc. Even 1 conduit with just 5x EGCs.
I noticed it because we had to pull a new feed into their switchboard right before permanent power got turned on to the building. This was literally the day before the utility was supposed to turn on power, They were this close to turning on a 2000A feeder with a single phase per conduit. And it was all metal conduit. They’d have burned that whole damn building down.
I told them they did it wrong and were going to start a fire. They didn’t believe me at first, so I had to escalate it to my GC’s safety coordinator, who had to bring it to their safety coordinator. They refused to call the utility to cancel turning on permanent power, so my safety guy and I had to intercept the utility guys when they showed up on site to tell them not to turn on power. Man was that other EC’s foreman PISSED, but he eventually did have to pull it all out and repull it correctly.
I did a tenant fit-out in a new building where the base-building was still under construction by a different electrical contractor when we started our buildout. The building had a penthouse switchboard that was fed with 5 parallel sets. Except the other EC pulled it as 1 phase per conduit. So they had 1 conduit with 5x a-phase conductors. Another with 5x b-phase, etc. Even 1 conduit with just 5x EGCs.
I noticed it because we had to pull a new feed into their switchboard right before permanent power got turned on to the building. This was literally the day before the utility was supposed to turn on power, They were this close to turning on a 2000A feeder with a single phase per conduit. And it was all metal conduit. They’d have burned that whole damn building down.
I told them they did it wrong and were going to start a fire. They didn’t believe me at first, so I had to escalate it to my GC’s safety coordinator, who had to bring it to their safety coordinator. They refused to call the utility to cancel turning on permanent power, so my safety guy and I had to intercept the utility guys when they showed up on site to tell them not to turn on power. Man was that other EC’s foreman PISSED, but he eventually did have to pull it all out and repull it correctly.