shared neutral

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dj94

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Hi ,
i have some em fixtures with built in batteries, the engineer screwed up and sourced the feed from a motorized breaker panel so there is no constant hot available to feed the em battery ballast,
His solution is to bring a hot wire only from another panel and use the 1 neutral from the motorized breaker panel for both circuits and ballasts.
seems wrong to me but i cant find any code issue..

is there a code issue with this install ???????
 
Absolutely!

300.3 Conductors.


(B) Conductors of the Same Circuit. All conductors of the
same circuit and, where used, the grounded conductor and all
equipment grounding conductors and bonding conductors shall
be contained within the same raceway, auxiliary gutter, cable
tray, cablebus assembly, trench, cable, or cord, unless otherwise
permitted in accordance with 300.3(B)(1)through (B)(4).
 
dj94 said:
His solution is to bring a hot wire only from another panel and use the 1 neutral from the motorized breaker panel for both circuits and ballasts.
seems wrong to me but i cant find any code issue..

is there a code issue with this install ???????
Click to expand...
Yes, it is a code issue and it is a huge safety issue.

Think about it. You go to the panel and turn off the breaker go back to whatever you are working on and test for power and verify that the power is indeed off so you start breaking connections and now one of those neutral wires that was at zero volts to ground is now 120V or 277V above ground because it's being fed from a different breaker, in a different panel that you didn't know about, and you get the nastiest shock of your life on something that you correctly killed the power to and correctly verified the power was off.

Tell the EE he needs to learn some more about electrical circuitry before he makes another suggestion that might get somebody hurt.
 
Jim1959 said:
Absolutely!

300.3 Conductors.


(B) Conductors of the Same Circuit. All conductors of the
same circuit and, where used, the grounded conductor and all
equipment grounding conductors and bonding conductors shall
be contained within the same raceway, auxiliary gutter, cable
tray, cablebus assembly, trench, cable, or cord, unless otherwise
permitted in accordance with 300.3(B)(1)through (B)(4).
Click to expand...

hi Jim ,
i see the code reference but if i carry a neutral and don't use it at the other end that covers the requirement.
still not telling me i cant land the hot only without some interpretation correct?
 
ActionDave said:
Yes, it is a code issue and it is a huge safety issue.

Think about it. You go to the panel and turn off the breaker go back to whatever you are working on and test for power and verify that the power is indeed off so you start breaking connections and now one of those neutral wires that was at zero volts to ground is now 120V or 277V above ground because it's being fed from a different breaker, in a different panel that you didn't know about, and you get the nastiest shock of your life on something that you correctly killed the power to and correctly verified the power was off.

Tell the EE he needs to learn some more about electrical circuitry before he makes another suggestion that might get somebody hurt.
Click to expand...

Hi Dave ,
I see your point fully but the EE wont back off of this without a direct code violation, for instance if each fixture is marked

"Danger 2 sources of power BP1-37 and RP-37"

wouldn't that "cover" the safety issue with the due diligence we put in by labeling the lights ??
 
dj94 said:
hi Jim ,
i see the code reference but if i carry a neutral and don't use it at the other end that covers the requirement.
still not telling me i cant land the hot only without some interpretation correct?
Click to expand...

If you have a wire in a pipe that you are not using then it's not a circuit conductor it's just a spare white wire plus if it is metal conduit you need to meet 300.20.
 
dj94 said:
hi Jim ,
i see the code reference but if i carry a neutral and don't use it at the other end that covers the requirement.
still not telling me i cant land the hot only without some interpretation correct?
Click to expand...

the hot and neutral (or whatever current carrying conductors of a circuit) must be run together. When they are in close proximity, they cancel eachother's magnetic fields. If this is not done, it can cause heating, radio interference at the least; especially in metallic conduit. sorry for the late reply, I was out on Friday.
 
dj94 said:
hi Jim ,
i see the code reference but if i carry a neutral and don't use it at the other end that covers the requirement.
still not telling me i cant land the hot only without some interpretation correct?
Click to expand...

dj94 said:
Hi Dave ,
I see your point fully but the EE wont back off of this without a direct code violation, for instance if each fixture is marked

"Danger 2 sources of power BP1-37 and RP-37"

wouldn't that "cover" the safety issue with the due diligence we put in by labeling the lights ??
Click to expand...

Perhaps this will help...

210.4 Multiwire Branch Circuits.

(A) General.Branch circuits recognized by this article shall
be permitted as multiwire circuits. A multiwire circuit shall be
permitted to be considered as multiple circuits. All conductors
of a multiwire branch circuit shall originate from the same
panelboard or similar distribution equipment.


Informational Note No. 1: A 3-phase, 4-wire, wye-connected​
power system used to supply power to nonlinear​
loads may necessitate that the power system design allow​
for the possibility of high harmonic currents on the neutral​
conductor.​

Informational Note No. 2: See 300.13(B) for continuity of​
grounded conductors on multiwire circuits.​

(B) Disconnecting Means. Each multiwire branch circuit
shall be provided with a means that will simultaneously
disconnect all ungrounded conductors at the point where
the branch circuit originates.


Informational Note: See 240.15(B) for information on the​
use of single-pole circuit breakers as the disconnecting means.​

(C) Line-to-Neutral Loads. Multiwire branch circuits
shall supply only line-to-neutral loads.

Exception No. 1: A multiwire branch circuit that supplies
only one utilization equipment.

Exception No. 2: Where all ungrounded conductors of the
multiwire branch circuit are opened simultaneously by the
branch-circuit overcurrent device.

(D) Grouping. The ungrounded and grounded circuit conductors
of each multiwire branch circuit shall be grouped
by cable ties or similar means in at least one location within
the panelboardorother point of origination.

Exception: The requirement for grouping shall not apply if
the circuit enters from a cable or raceway unique to the
circuit that makes the grouping obvious or if the conductors
are identified at their terminations with numbered wire
markers corresponding to the appropriate circuit number.
Click to expand...

90.1 Purpose.

(A) Practical Safeguarding.The purpose of this Code is
the practical safeguarding of persons and property from
hazards arising from the use of electricity. This Code is not
intended as a design specification or an instruction manual
for untrained persons.

...
Click to expand...
 
thanks Guys,
the EE is still insisting on doing it the wrong way (his way) he did re issue the response to at lease use the same phase from each panel so hopefully the lights wont explode when the test button is pushed.
(i kind of hope they do) :D
 
dj94 said:
thanks Guys,
the EE is still insisting on doing it the wrong way (his way) he did re issue the response to at lease use the same phase from each panel so hopefully the lights wont explode when the test button is pushed.
(i kind of hope they do) :D
Click to expand...
Is there an inspector that could get involved?

Roger
 
It doesn't make any sense. If he can pull a phase, he can pull a neutral as well. I wouldn't sit back and let him do it that way.
 
dj94 said:
thanks Guys,
the EE is still insisting on doing it the wrong way (his way) he did re issue the response to at lease use the same phase from each panel so hopefully the lights wont explode when the test button is pushed.
(i kind of hope they do) :D
Click to expand...
No way I would do this. He's an EE not a diety. Tell him no, or tell his boss or somebody what is going on.
 
dj94 said:
thanks Guys,
the EE is still insisting on doing it the wrong way (his way) he did re issue the response to at lease use the same phase from each panel so hopefully the lights wont explode when the test button is pushed.
(i kind of hope they do) :D
Click to expand...

If he used the same phase, the neutral current could double.
 
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