History Please - Taps ahead of Mains for Emergency Lights

busman

busman

Senior Member
Location
Northern Virginia
Occupation
Master Electrician / Electrical Engineer
All,

You are a treasure house of information. I have a commercial building that is approximately 60 years old. Has a 2-pole fused disconnect (Edison type - 20A) that appears to be tapped from ahead of the 600A main. So far I have found that it powers some of the emergency lights and the control (coil) voltage for the kitchen range hood relays. Was this allowed or required in the past? I don't think it is legal now. I can provide photos if that would help. Any information appreciated.

Thanks as always.

Mark
 
I vaguely remember running into something like that years ago. Given as we can connect fire pumps ahead of the usual main, connecting emergency lights there seems quite reasonable. (I was going to check my 1978 code book, but can't find it at the moment.)
 
Unsure about the Code reference or applicability but I have the installation on services dating back in the 1950s.
 
don_resqcapt19 said:
A tap ahead of the service disconnect, but not within the service disconnect enclosure was permitted to be the source of power for emergency systems through the 1993 code. 700-12(e)
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Did such systems have to follow the normal tap rules of 240? Because it would be hard to get 200 amp conductors in a 2 pole plug fuse disconnect.
 
CoolWill said:
Did such systems have to follow the normal tap rules of 240? Because it would be hard to get 200 amp conductors in a 2 pole plug fuse disconnect.
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If the "tap" is on the line side of the service, the Art 240 tap rules don;t apply.
(In my experience is was commonplace to see a violation concerning the conductors being "tapped" to other service disconnect lugs)
 
don_resqcapt19 said:
A tap ahead of the service disconnect, but not within the service disconnect enclosure was permitted to be the source of power for emergency systems through the 1993 code. 700-12(e)
Click to expand...
Thanks. My earliest Code book is 1996, so explains why I did not know that. These are appear to be tapped in the service panelboard. I would need a second set of trained hands to take the cover off this large panelboard, so I have not done that yet. I'm going to submit a proposal to abandon that disconnect and feed those that MWBC from one of the regular panelboards.

Thanks to all.

Mark
 
Before moving the circuits I would suggest you investigate if Art 700 or 701 are applicable and, if so, check the appropriate Sections (***.12)
 
augie47 said:
Before moving the circuits I would suggest you investigate if Art 700 or 701 are applicable and, if so, check the appropriate Sections (***.12)
Click to expand...
augie47 said:
Before moving the circuits I would suggest you investigate if Art 700 or 701 are applicable and, if so, check the appropriate Sections (***.12)
Click to expand...
Was there something particular you had in mind? The circuit is powering multiple battery backup lights (the small wall mount LED type) in a hall that is rented out.

Thanks,

Mark
 
It was simply a precautionary note, not knowing the particulars, that the relevant authority might have classified the installation as "Emergency" or
"Legally Required" which would effect the required source of power.
From your latest post it would appear at most it would be a 701.12(C) application.
 
busman said:
All,

You are a treasure house of information. I have a commercial building that is approximately 60 years old. Has a 2-pole fused disconnect (Edison type - 20A) that appears to be tapped from ahead of the 600A main. So far I have found that it powers some of the emergency lights and the control (coil) voltage for the kitchen range hood relays. Was this allowed or required in the past? I don't think it is legal now. I can provide photos if that would help. Any information appreciated.

Thanks as always.

Mark
Click to expand...
IT is still allowed now and done all the time See 230.40 EX#2. Perhaps I am misunderstanding something? Is this disconnect grouped with the other service disconnects.?
 
electrofelon said:
IT is still allowed now and done all the time See 230.40 EX#2. Perhaps I am misunderstanding something? Is this disconnect grouped with the other service disconnects.?
Click to expand...
That is not a permitted source for power to Article 700 circuits. The last code that permitted such a tap to power Article 700 circuits was the 1993 code.
This thread was about power to emergency lights, which would be an Article 700 circuit.
However it appears that since the original installation the emergency lighting has been converted to unit equipment with internal battery back-up. The normal power to that type of equipment is not an Article 700 circuit, however if the unit has remote heads, the wiring between the unit and the remote head is an Article 700 circuit.
 
augie47 said:
Before moving the circuits I would suggest you investigate if Art 700 or 701 are applicable and, if so, check the appropriate Sections (***.12)
Click to expand...
Yes, Art. 700.12 applies. These are what they term Unit Equipment in sub-section F. After reading thru this, they are clearly not on the correct branch circuits. I have no idea when they were added to the building. This building used to be a furniture store and was bought by a not-for-profit and converted to meeting spaces and a rental hall with a commercial kitchen and office space. At the moment, I'm just trying to solve their kitchen hood issues. These involved a shorted coil on a contactor and two wires that had come loose and shorted.

Thanks,

Mark
 
busman said:
Yes, Art. 700.12 applies. These are what they term Unit Equipment in sub-section F. After reading thru this, they are clearly not on the correct branch circuits. I have no idea when they were added to the building. This building used to be a furniture store and was bought by a not-for-profit and converted to meeting spaces and a rental hall with a commercial kitchen and office space. At the moment, I'm just trying to solve their kitchen hood issues. These involved a shorted coil on a contactor and two wires that had come loose and shorted.

Thanks,

Mark
Click to expand...
I expect that the original installation did not involve unit equipment, but lighting directly supplied from the emergency circuit that was supplied from a tap ahead of the service disconnect.
 
don_resqcapt19 said:
That is not a permitted source for power to Article 700 circuits. The last code that permitted such a tap to power Article 700 circuits was the 1993 code.
This thread was about power to emergency lights, which would be an Article 700 circuit.
However it appears that since the original installation the emergency lighting has been converted to unit equipment with internal battery back-up. The normal power to that type of equipment is not an Article 700 circuit, however if the unit has remote heads, the wiring between the unit and the remote head is an Article 700 circuit.
Click to expand...
Oh ok, right, I was just thinking generally about tapping service conductors to an additional disconnect. So the issue would be because they need to originate in the same branch circuit as the normal lighting?
 
busman said:
Yes, Art. 700.12 applies. These are what they term Unit Equipment in sub-section F. After reading thru this, they are clearly not on the correct branch circuits. I have no idea when they were added to the building. This building used to be a furniture store and was bought by a not-for-profit and converted to meeting spaces and a rental hall with a commercial kitchen and office space. At the moment, I'm just trying to solve their kitchen hood issues. These involved a shorted coil on a contactor and two wires that had come loose and shorted.

Thanks,

Mark
Click to expand...
Regardless of the parentage of the emergency lights, certainly the kitchen range would not have been permitted to be connected in this manner.
 
electrofelon said:
Oh ok, right, I was just thinking generally about tapping service conductors to an additional disconnect. So the issue would be because they need to originate in the same branch circuit as the normal lighting?
Click to expand...
That would be the current issue with unit lights having been installed. Often, in the past, the tap ahead of the service was used for egress and exit lighting that was not unit equipment. When the unit lighting was installed, those units should have been connected to branch circuits from the same panelboard that supplies the normal lighting in the area. The unit equipment is no longer required to be on the same circuit as it was in the past.
 
gadfly56 said:
Regardless of the parentage of the emergency lights, certainly the kitchen range would not have been permitted to be connected in this manner.
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There is actually a subtle point here. It is not the range equipment that is on this disconnect, it is the control (coil) voltage that is on it. Doesn't make much sense since there would be powered to control, if the main was off.

Mark
 
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