Here's a situation that I haven't run into before.
We are troubleshooting exit lights and emegency lights in an older school of 3 buildings. All 3 buildings have the same 227v volt 20 amp circuit for Exits & Emegergency lighting. The actual Classroom and Administration building is where the power source originated from and it continues into the two unattached gyms that are only connected to the main bldg. via a covered walkway. Conduit and circuit are run underneath these walkways; or in some cases on top; to the gyms.
The Main bldg. has it's own Service Feeder and Distribution and the Gyms also have their own separate Service Feeder & distribution.
There is not an Emergency Stand-by system in place anywhere on this property.
My question is - Is there a NEC restriction to having the same continuos ciruit and raceway feeding from the Main Building to the two Gyms? If there is; I haven't been able to find it in the 700 Articles.
Since there is no Emergency "System", on site, are the Emergency Fixtures & Signs "Unit Equipment" per 700.12(E)? If so, the local lighting circuit needs to be the source of supply. This would seem to prohibit the circuiting you describe.
Dave, Considering 700.12(E), 700.15 seems to pertain to facilities that have an "Emergency System". It appears that the facility in question does not have one, so I'm guessing that thes are "unit equipment" The middle of the second paragraph of 700.12(E) states that the branch circuit feeding the unit equipment be the same branch circuit that serves the normal lighting in that area.
More discussion may be in order?
Re: Exit Luminaire Circuiting#49519 03/09/0508:31 AM03/09/0508:31 AM
Egress lighting shall be connected to the local lighting circuit, ahead of the switch. Where there are more than three (3) local lighting circuits, an independent circuit may be installed, provided with a 'breaker lock'. (Meaning in a large open area with 4 to xx lighting circuits)
What you describe sounds like the "old" way, they used to tap a circuit ahead of the main (with OCP sized to the conductor) and feed all the "exit" units.
Dave55: there is few options you can use with the HID lighting systems.
1] you can use the standby quatz system intreaged with the ballast system which it mean that the quatz light bulb light up both cold and hot start until the light get up to about 50% brightness then switched off and HID bulb will take care the rest of it
2] have the seprated stand by circuit for the HID lighting system but this will really increase the cost of materal and labour for this
Dave: I have to agree with Pierre, and have a few 'others' for your consideration:
Best solution for a NEW install is to get the quartz restrike option installed in the HID fixtures when ordering.
A common solution used widely here is: Install a time delay (off) on the exit/emergency circuit that starts the set time delay upon restoration of normal power. (usually 10 to 15 min). That allows the HID's to re-strike.
Some guys install fluorescent channels in the egress areas as needed that 'light' instantaneously upon power restoration. This is dependent on the size of the jobsite, and some customers don't like the additional fixtures.
We usually install a phase loss monitor relay at the LP, that the exit/em circuit(s) are wired to, in case of only a phase loss, and not a full power fail.
Again, the ultimate solution needs a lot of 'answers' to find a solution. Don't despair, there's always a Code compliant answer!