This is for anyone who is familiar with the NEC requirements for multi-wire branch circuits. The code sections in question is NEC 210.4. The question of using multi-pole breakers or handle ties to disconnect the ungrounded conductors of a shared neutral circuit or using dedicated neutrals is...
Thanks cdafd. I am looking at the life safety floor plan and a lot of doors are labeled "Smoke Tight" but not the one leading from the dorm to the corridor. The corridor leads to dayroom accesses through secure vestibules. Vestibules are enclosed by same one hour fire and smoke barrier as...
I have not been able to find a clear definition for what is considered "contiguous spaces" within a building. In a case I am looking at I have a secure corridor leading from a detention facility dorm sleeping area. All doors into the secure corridor or normally locked and closed including the...
Thanks. Let me add a complication to this situation that I should have explained before. The contractor had already begun the work of replacing the service with the blessing of the power company. The old service has been removed. Existing transformer enclosure still there for now but...
I got a call from an electrician and building owner who had already started work to convert an existing 240/120 volt, three-phase delta service to 120/208-volt wye. The power company wanted to get rid of the old transformers and service and provide a new pad mounted transformer for the building...
Thanks everyone. In the last elevator modernization I did we were specifically told by the inspector not to install smoke detectors in the elevator shafts if there were no sprinklers but I had never read that in any of the codes.
I am working on an elevator modernization project. It is a hydraulic type elevator. This building has no fire protection sprinkler system. I have smoke detectors in the elevator lobbies and elevator machine room for elevator recall purposes. Usually when we have sprinkler heads in the...
This is an NFPA 70 and 99 questsion. We are having to add steam boilers for an Ambulatory Surgical Center. They are electrcally powered. The serve sterilizing equipment for the facility. Do these boilers have to be connected to emergency power?
I am not getting a good sense about the actual requirements for grounding the raised floor system. I've read about recommendations but not hard, fast requirements. In a standard raised floor application, no computer rooms or heavy data equipment, I would bond to any column, and bond every ten...
I recently specified a minimum 225-amp, 3-pole, 240 volt rated electrical contactor for a project. It's function is simply to remove power from a panelboard feeding cooking equipment under a kitchen hood when the hood fire protection system is activated. So there will be very little switching...
