AskCodeMan

I inspected a home where the panel is mounted on exterior wall line in a home built in the mid 70's.There is rusted spots which indicate moisture.I would not think this would be allowed by codes since exterior walls are insulated and water diffusion in the wall line.Could someone help me on this.I've looked in the NEC but to no avail.This doesn't seem right.
1) Safety from nails piercing conductors,water intrusion,and the close prox to combustible insulation required in exterior wall.

Please Help out if you can answer this one

InspectorHolmes wrote:panel is mounted on exterior wall line

Would you clarify what you are describing?

Do you mean the enclosure is "surface mounted *ON* the wall" or "recess mounted *IN* the wall"?

1) Safety from nails piercing conductors,water intrusion,and the close prox to combustible insulation required in exterior wall.

Not sure what you are asking there, but here are my guesses as to what you are asking:
- NM cable requires protection plates when installed within 1-1/4 inch of the face of the stud.
- If an enclosure is in an area where it will get wet, such as outside, then it needs to be a raintight type enclosure.
- There are no requirements regarding electrical enclosure clearance to combustible material as the enclosure is not supposed to get that hot, and any fire caused by a problem in the enclosure is supposed to be contained in that enclosure.

I will also add the following that seems to give a rule that can be considered here. It is short and sweet:

110.12(B) Integrity of Electrical Equipment and Connections. Internal parts of electrical equipment, including busbars, wiring terminals, insulators, and other surfaces, shall not be damaged or contaminated by foreign materials such as paint, plaster, cleaners, abrasives, or corrosive residues. There shall be no damaged parts that may adversely affect safe operation or mechanical strength of the equipment such as parts that are broken; bent; cut; or deteriorated by corrosion, chemical action, or overheating.

My thoughts lead me to the underrlined part here.

Thanks! The panel cover was rusting in many areas on the exterior.
There were no signs of water,however there were several double taps.

Is the enclosure recessed into the wall or surface mounted?

It makes a difference, other questions may follow which will also make a difference in how you write it up.