As usual, never consider the following commentary associated with these photos as a formal interpretation of the National Electrical Code (NEC). Without criticizing anyone or any product, the following scenarios present us with serious safety questions.


Timothy Clark, owner, TEC Electric, Dumfries, Va., ran across this interesting installation, which the homeowner told him was completed by a contractor. In his e-mail to EC&M, Clark pointed out the 15A piggyback installed above the main fuses.

This type of do-it-yourself work isn't uncommon and violates the requirements of 90.7, which in part states, “It is the intent of this Code that factory-installed internal wiring or the construction of equipment need not be inspected at the time of installation of the equipment, except to detect alterations or damage, if the equipment has been listed by a qualified electrical testing laboratory that's recognized as having the facilities described in the preceding paragraph and that requires suitability for installation in accordance with this Code.

“FPN No. 1: See requirements in 110.3.

“FPN No. 2: ‘Listed’ is defined in Article 100.

“FPN No. 3: Annex A contains an informative list of product safety standards for electrical equipment.”


Gerry Jensen, journeyman, Freeman's Electrical Service, Inc., Rapid City, S.D., noticed this service mast recently while performing a service call on the house next door. In his e-mail to EC&M, he notes, “It appears to be ‘plumbed’ rather than installed with conduit and approved fittings. There is little in means of support and there seems to be another wire coming out of the weather head, possibly an NM cable. Would this installation fall under the category of ‘electrical and plumbing code violations’?”

Service-entrance conductors shall be installed as per the wiring method used and shall be limited to the methods shown in 230.43. Sec. 230.28 permits the service mast to act as a support for the service-drop conductors, as long as it's of adequate strength. If it isn't, braces or guys must be used to withstand the strain imposed by the conductors. In addition, when a raceway-type service mast is used, all raceway fittings are required to be identified for use with service masts. Only power service-drop conductors can be attached to a service mast.

Plumbing fittings can't be used in an electrical installation because these items aren't designed to be used to ensure grounding and bonding continuity. They can also lead to damage of installed conductors.

Found a Code violation? E-mail your photos to Joe Tedesco at