We have an inside breaker box and want to install a dedicated line to an exterior outlet. In order to do that we are thinking to cut a hole in the back of the breaker box and another in the outside wall of the house to push the cable that way and after that using conduit up to the outlet. Are there any restrictions for that in Texas?
Electrical – Does code allow cutting a hole in the back of an indoor breaker box
circuit breakercuttingelectrical-panelholewalls
Related Solutions
Since it's a Ground Fault Circuit Interrupter (GFCI) breaker, it's very likely that you have a ground fault.
GFCIs work by detecting an imbalance in current between the ungrounded (hot), and grounded (neutral) conductors. This is why you only see the trip when the circuit is under load. If there is 0 current flow, the current is balanced.
I'd start by inspecting the receptacle. Turn off the breaker, then open up the box where the receptacle is installed. Look for damage to the receptacle itself, or water/moisture in the box.
For outdoor installations you should always have a weatherproof box, and a cover that is weatherproof even when the receptacle is in use.
Without being able to see the cables as they enter the cabinet; or the ability to touch or trace them, here is what I assume is going on.
Definitions:
Grounded (neutral) from the service
A typical single split phase service is made up of 3 wires. Two ungrounded (hot) conductors, and one grounded (neutral) conductor. The ungrounded (hot) conductors will connect to the main service panel through a disconnect (usually a large breaker), while the grounded (neutral) connects to the neutral lug. The neutral lug will be bonded (electrically connected) to the neutral bus bar, and all grounded (neutral) branch circuit conductors will terminate at the neutral bus.
Grounding Electrode Conductor
This conductor is used to connect the grounding electrode (ground rod, etc.), to the grounding bus in the panel. All equipment grounding conductors will be connected to this bus.
Bonding Jumper
The bonding jumper is used to bond (electrically connect), the un-energized metal parts of the panel to the grounding system.
Assumption:
Since it appears that (what I assume is) the grounding electrode conductor terminates at the neutral bus, I'm also assuming that this is the main service disconnect. This leads me to believe that the neutral and grounding buses are bonded (electrically connected). In which case, technically, grounded (neutral) branch circuit conductors can terminate at the grounding bus.
So you have two options:
Terminate the grounded (neutral) from the new circuit to the grounding bus.
Move the green wire that is terminated on the neutral bus, to the grounding bus. Then terminate the grounded (neutral) from the new circuit, to the freed up slot on the neutral bus.
Additional Information and Code Compliance:
Number of Conductors
Since this is a new circuit, it has to be installed to current code standards.
National Electrical Code 2011
ARTICLE 250 — GROUNDING AND BONDING
VI. Equipment Grounding and Equipment Grounding Conductors
250.140 Frames of Ranges and Clothes Dryers. Frames of electric ranges, wall-mounted ovens, counter-mounted cooking units, clothes dryers, and outlet or junction boxes that are part of the circuit for these appliances shall be connected to the equipment grounding conductor in the manner specified by 250.134 or 250.138.
Which in this case means installing a NEMA 14 receptacle for the dryer, and a proper grounding conductor.
You'll have to follow the dryer manufacturers installation instructions for upgrading to a 4 wire cord. For more information see this answer, and this answer.
Since you've said that you're already using 4 wire cable, you'll simply have to terminate the grounding conductor in the cable to the grounding bus in the service panel. Then connect the other end of the grounding conductor to the grounding terminal in the dryer receptacle.
Size of Conductors
You'll also want to be sure that you're using the proper size breaker and conductors. In the case of a dryer, you'll typically use a 30 ampere breaker and 10 AWG conductors (depending on the length of the run). However, you'll want to check the dryer manufacturers installation instructions to verify this.
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Best Answer
While it may be technically OK (I am not a code expert), unless it must be directly behind the panel, far better would be to connect to one of the sides or top or bottom, then turn 90 degrees to go through the wall. You might need an extra little piece of conduit or two, but if there is ever a need to replace the entire panel, it will be much easier not having to worry about lining up a hole in the new panel.