Branch Circuit Transfer Switching
Branch Circuit Transfer Switching
(OP)
Forgive me if I sound ignorant (I'm a new EE fresh out of school). Is it "unconventional" or a code violation to place a transfer switch on the load side of a branch circuit breaker of a lighting panel to supply the branch with alternate power (from a generator)?






RE: Branch Circuit Transfer Switching
If you are looking for guidance to a specific task, you need to post more details as to what you are trying to acheive.
In fact, for self-contained emergecny lighting units (with battery and charger), each unit contains a trasfer relay which amounts a transfer switch on load side of the branch circuit. This is different than using generator as emergency source.
RE: Branch Circuit Transfer Switching
Special attention should be given to the transfer switch-grounding requirement. Please see the enclose sites.
http://www.energy.ca.gov/distgen/interconnection/equipment.html
http://www.ecmweb.com/mag/electric_grounding_onsite_power/
RE: Branch Circuit Transfer Switching
1. I should have stated that the switch is to be a manual switch not an ATS.
2. The generator is in fact an emergency generator, but my client is trying to upgrade the emergency lighting so that E-lights do not depend on the generator but CAN be switched over (manually) to be powered by the generator in cases of extented building outage (let say, for maintenance).
3. The building is old (completed in early 1950's). There are a number of designated emergency panels, each having its own ATS to switch to "emergency power".
The "non-emergency" panels in the building do not have shunt trip breakers. And I need to power specific branch circuits (like circuits that have battery backed E-lights on them) by switching manually to the generator.
The main idea being that if a power failure occurs the emergency lights will switch to battery mode be it a fluorescent emergency ballast, or wall mounted "aimable" battery power light. Then, if it is desired, someone can manually switch the lights to generator power (and the e-light batteries will be charging even though the normal power is out). BUT, I cannot power an entire lighting panel, but only want to power few of the branches. I hope this is more clear. Thanks.
RE: Branch Circuit Transfer Switching
One MTS and feeding a 'emergency' panel could be the best soultion, imho. You will have to wire the individual emergency circuits to this panel.
RE: Branch Circuit Transfer Switching
Mike
RE: Branch Circuit Transfer Switching
RE: Branch Circuit Transfer Switching
Thanks to everyone for their input.
RE: Branch Circuit Transfer Switching
Per Article 5-10.3.5 of NFPA 101-1997 (Life Safety Code) “…the exit signs shall be illuminated by the emergency lighting facilities.”
Article 5-9.1.2 of Section 5.9 (Emergency Lighting) of NFPA 101 states that “Where emergency lighting is provided by a prime-mover operated electric generator, a delay of not more than 10 seconds shall be permitted.”