Individual neutrals
Individual neutrals
OK guys, I've got to weigh in on this issue. Have any of you worked in a facility that was over 60 years old? Things get moved around all the time. Individual neutrals do increase initial installation costs, but eliminate many problems down the road.
I've seen and had to help correct many issues related to MWBC wiring years after it was installed. When they were installed, there were not the non-linear loads of today's facilities (i.e. electronic ballasts and switching power supplies in computers). Ever had to troubleshoot a problem where a main breaker in a panel is tripping even though none of the circuits are over 10A and the total load on the panel is much less than the MCB? Ever heard of harmonics (created by the non-linear loads)?
The main reason for specifying dedicated neutrals is to eliminate these issues later. Yes, there is a cost, but it is very expensive to go back and figure out things later. The cost of downtime due to tripped breakers, burned wires, etc is very high, especially in a situation where the burden rate of electricians is approaching $80-$90/hr. I am talking burden rate, not pay rate. Also, what is the cost of lost data and work?
Another thing, just because an electrician is a journeyman, doesn't mean that he is qualified. I've worked with many (>100) "skilled trades" electricians that can't wire a simple 3-way switching circuit. Earlier in the discussion, a comment was made about things being an insult to an electrician. Well, let me tell you, if everyone did things properly and safe, do you think that the NEC would be so thick? NO!!! The NEC is so large to protect people.
Sorry for getting on my soapbox, but I hate it when people think that Engineers don't know anything. What I've seen is that many times, these same people are the ones that don't follow the print and specs on a job and then later wonder "why doesn't it work".
KAS...