Emergency Lighting

[websparky]

Re: Emergency Lighting

Ron,
Thanks for your input. It seems to me that several years ago we were required to connect the emergency and exits to the same circuit that supplied the area or room lighting. When I have inspected commercial jobs over the last year and prior to that as an electrician installing systems, we seemed to stop that practice and the plans came through with separate egress circuits. It seems to me we should return to the old way. How else could we comply with the building codes?

 

[websparky]

Re: Emergency Lighting

Don,
You must be kidding! See if you can find one of the typical units that are installed these days.

 

[iwire]

Re: Emergency Lighting

Originally posted by websparky:
It seems to me that several years ago we were required to connect the emergency and exits to the same circuit that supplied the area or room lighting. When I have inspected commercial jobs over the last year and prior to that as an electrician installing systems, we seemed to stop that practice and the plans came through with separate egress circuits.

Dave they may be following the NEC or ignoring it, would that not be your job to make sure of?

Part of 700.12(E)

The branch circuit feeding the unit equipment shall be the same branch circuit as that serving the normal lighting in the area and connected ahead of any local switches.

But there is also an exception.

700.12(E) Exception: In a separate and uninterrupted area supplied by a minimum of three normal lighting circuits, a separate branch circuit for unit equipment shall be permitted if it originates from the same panelboard as that of the normal lighting circuits and is provided with a lock-on feature.

Originally posted by websparky:
You must be kidding! See if you can find one of the typical units that are installed these days.

Does this mean you do not believe typical EBUs have fused outputs?

 

[websparky]

Re: Emergency Lighting

Bob,
700.12(E)??? We must have different code books?

 

[websparky]

Re: Emergency Lighting

Bob,
The "fuse" that Don brought up doesn't apply to unit equipment. Besides, don't generators have fuses or circuit breakers?

 

[don_resqcapt19]

Re: Emergency Lighting

Dave,

Don,
You must be kidding! See if you can find one of the typical units that are installed these days.

That was the only online document that I could find without spending a lot of time. The unit equipment that I installed last week had a fuse between the battery and the lights. This is very common in that type of equipment and the equipment would be a fire hazard without the fuses.

The "fuse" that Don brought up doesn't apply to unit equipment.

You brought up 7.9.2.2 that prohibits fuses. That section does not specify where the fuse is.
The wording of the section appears to prohibit any overcurrent device anywhere in the emergency lighting circuit, even within the unit equipment itself.
Don

 

[websparky]

Re: Emergency Lighting

Don,
This is in reference to the "normal" power failing due to a fuse or a circuit breaker. Has absolutely nothing to do with the "emergency" power source.

 

[iwire]

Re: Emergency Lighting

Originally posted by websparky:
Bob,
700.12(E)??? We must have different code books?

Yes Dave 2002 700.12(E) in 2005 it moved to 700.12(F) sorry if that escaped you.


2002 NEC

III. Sources of Power
700.12 General Requirements.

(E) Unit Equipment. Individual unit equipment for emergency illumination shall consist of the following:

(1)A rechargeable battery

(2)A battery charging means

(3)Provisions for one or more lamps mounted on the equipment, or shall be permitted to have terminals for remote lamps, or both

(4)A relaying device arranged to energize the lamps automatically upon failure of the supply to the unit equipment

The batteries shall be of suitable rating and capacity to supply and maintain at not less than 871/2 percent of the nominal battery voltage for the total lamp load associated with the unit for a period of at least 11/2 hours, or the unit equipment shall supply and maintain not less than 60 percent of the initial emergency illumination for a period of at least 11/2 hours. Storage batteries, whether of the acid or alkali type, shall be designed and constructed to meet the requirements of emergency service.
Unit equipment shall be permanently fixed in place (i.e., not portable) and shall have all wiring to each unit installed in accordance with the requirements of any of the wiring methods in Chapter 3. Flexible cord-and-plug connection shall be permitted, provided that the cord does not exceed 900 mm (3 ft) in length. The branch circuit feeding the unit equipment shall be the same branch circuit as that serving the normal lighting in the area and connected ahead of any local switches. The branch circuit that feeds unit equipment shall be clearly identified at the distribution panel. Emergency luminaires (illumination fixtures) that obtain power from a unit equipment and are not part of the unit equipment shall be wired to the unit equipment as required by 700.9 and by one of the wiring methods of Chapter 3.

Exception: In a separate and uninterrupted area supplied by a minimum of three normal lighting circuits, a separate branch circuit for unit equipment shall be permitted if it originates from the same panelboard as that of the normal lighting circuits and is provided with a lock-on feature.

[ December 28, 2005, 04:27 AM: Message edited by: iwire ]

 

[sceepe]

Re: Emergency Lighting

quote:NFPA 101 Life Safety Code 2000
7.9.2.2*
The emergency lighting system shall be arranged to provide the required illumination automatically in the event of any of the following:
(1) Interruption of normal lighting such as any failure of a public utility or other outside electrical power supply
(2) Opening of a circuit breaker or fuse
(3) Manual act(s), including accidental opening of a switch controlling normal lighting facilities

Don,
How does a generator provide for (2)above?

Item #2 is provided for in that you have 2 separate systems. Ok lets imagine long corridor every 4th light is an "emergency" light which is wired through a transfer switch to a generator. If CB trips in the emergency light circuit every 4th light goes out. No biggie still plenty of light. If fuse blows in the circuit suppling the "normal" lighting, the "emergency" lights are still on and you have every fourth light burning to get you out of the area safely. As I said before area will not be in total darkness unless you lose two CBs.

quote:Both sources of illumination should be in regular simultaneous operation whenever the building is occupied during periods of darkness.

I have never seen an emergency generator running "in regular simultaneous operation". The word simultaneous means "at the same time". Do the generators in Mass. run 24/7?

No. Everything downstream of the transfer switch runs simultaneously and 24/7. (except for the 10 seconds it takes the gen set to fire up)

Ron,
Thanks for your input. It seems to me that several years ago we were required to connect the emergency and exits to the same circuit that supplied the area or room lighting. When I have inspected commercial jobs over the last year and prior to that as an electrician installing systems, we seemed to stop that practice and the plans came through with separate egress circuits. It seems to me we should return to the old way. How else could we comply with the building codes?

No No No, If you use battery pack units for emergency lighting you are required (and always have been required to) wire the unit fixtures to the same circuit that supplies the normal lighting for the space.

 

[don_resqcapt19]

Re: Emergency Lighting

Dave,

This is in reference to the "normal" power failing due to a fuse or a circuit breaker. Has absolutely nothing to do with the "emergency" power source.

I agree that is the intent of the rule, but the words do not say that.
Don

 

[iwire]

Re: Emergency Lighting

Originally posted by sceepe:
No No No, If you use battery pack units for emergency lighting you are required (and always have been required to) wire the unit fixtures to the same circuit that supplies the normal lighting for the space.

You are not always required by the NEC to use the same circuit, perhaps another code?

1990 NEC 700-12(f)

1996 NEC 700-12(e)

1999 NEC 700-12(e)

2002 NEC 700.12(E)

2005 NEC 700.12(F)

For better or worse all have this same exception.

Exception: In a separate and uninterrupted area supplied by a minimum of three normal lighting circuits, a separate branch circuit for unit equipment shall be permitted if it originates from the same panelboard as that of the normal lighting circuits and is provided with a lock-on feature.

 

[websparky]

Re: Emergency Lighting

Bob,
I think you hit the nail on the head. I believe there have been relaxed plan reviews and inspections of these requirements resulting in designers and installers running a circuit everywhere for the emergency lighting regardless of the full application of the exception.

Miles,
I said:

..we were required to connect the emergency and exits to the same circuit that supplied the area or room lighting.

You said:

..you are required (and always have been required to) wire the unit fixtures to the same circuit that supplies the normal lighting for the space.

Didn't we both say the same thing?

As far as the generator system and your explanation, it makes perfect sense.

Thanks to everyone!

 

[iwire]

Re: Emergency Lighting

Originally posted by websparky:
Bob,
I think you hit the nail on the head. I believe there have been relaxed plan reviews and inspections of these requirements resulting in designers and installers running a circuit everywhere for the emergency lighting regardless of the full application of the exception.

Thanks and it has been interesting looking at 101.

Edit error A

[ December 28, 2005, 07:57 PM: Message edited by: iwire ]