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Wires running across the Live Bus of a panelboard.


hot-wires-across-busA number of Inspectors have raised a concern about wires crossing the bus in an electrical panel.  Inspectors are being questioned by Realtors as to the codes that apply to these concerns.   We frequently find our members in a situation where a safety concern of the inspector is not specifically covered with a code. 

We are aware of the concern and have reached out to a number of electricians, the majority of which have replied that regardless of whether the wire is hot, grounded or ground they should not cross the bus bar, but instead be routed in the cable trays around the breakers. 

As we have a minority of electricians take an opposing view, we asked for an official position from the  Electrical Safety Authority.  As usual, they came through with flying colours.


ESA Position

For properly insulated conductors, other than Rule 12-3032, there are no rules which would prohibit them from crossing a bare buss. The conductors are insulated to the voltage in the panelboard.

But this installation might be in violation” of  “the following Code Rule:

12-3032  Wiring space in enclosures

(3)   Conductors entering enclosures shall enter such enclosures as near as practicable to their terminal fittings

Which means that when installing a branch circuit and there is sufficient space on the side of the panel where the breaker terminals are located for the conductor to enter the panel,  then this would be the preferred wiring method, and would be in compliance with 12-3032.  

Unfortunately, it has the word practicable, and determination of what is practicable is always in question.  The intent of this rule is to limit the length of conductors inside an enclosure.

Our take on this.

The definition of the word “practicable” means that an action is possible.   Had the word been “practical” we would have been concerned that it was more of a  subjective term identifying that the action is sensible.

While the ESA position is that the use of the word “practicable” is unfortunate, we do not see it as so, with respect to the decision-making process, from an inspectors perspective.

By using the word “practicable” it identifies that, following the intent of the rule, if it is “possible” to reduce the length of the conductors by having them enter close to the terminal connection (breaker, bus etc.) then it is the required method, (as defined by the word “shall” in code 12-3032).  If it is possible, and not done that way, then it could be considered in violation of the code, which is what we got from the majority of the electricians we approached.

It should also be remembered that in a panel, breakers can be installed on both sides of the panelboard, and simply moving the breaker might provide an opportunity for the wiring in the panel enclosure to comply with code 12-3032.

So, on inspecting a panel you see wires crossing the live bus of the panelboard you need make a decision based upon what you find and from that one of three opinions.

  1. If the wires are not insulated in any way (i.e. Bare ground wires, nicks or burns in the sheathing or missing sheathing as it crosses the buss) this is a defect and needs to be referred to a licensed electrician for immediate repair.
  2. If the conductors are insulated, with no signs of damage to the sheathing, and cross the bus just to provide a “neat” panel, but there are knock-out points closer to the breaker that allows for wire entry without crossing the bus, this should be called out as a concern, stating that the wiring does not meet preferred wiring standards of the Ontario Electrical Safety Code and recommend further Inspection by a licensed electrician as desired.
  3. If the conductors are fully insulated, with no signs of damage to the sheathing, and cross the bus and there appears to be no way to route the conductors into the panel to their terminal locations through a knock-out closer to the breaker or bus connection, then it is not considered a code violation.  If movement and installation of a breaker to the entry side of the bus appears to be possible, again you could recommend further inspection by a licensed electrician to implement the changes.  Remember that just because there appears to be space on one side of a bus, it may not be possible to move a breaker from one side to the other because of circuit balancing.