Illustrated Catastrophes

Jun 1, 2005 12:00 PM, By Joe Tedesco, NEC Columnist

More Code catastrophes

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.

All references are based on the 2005 NEC.

JUST TRY TO BLOW THIS “FUSE”

Doug Kidd, P.E., Kincaid*Bryant, Lynchburg, Va., found this installation recently while designing a chiller replacement at a state college. He noted that the original installation was completed in 1985 as a part of a major building renovation. The design used a 2,000A high-pressure contact main switch in the switchboard as the building service disconnect. “Maybe the electrician was in a hurry to get temporary power to the building,” Kidd wrote.

In addition, he noted that only three parallel sets of 500 kcmil were used for the service lateral. “That's all the electrician installed,” he said. “Needless to say, we advised the owner to immediately replace the ‘fuses,’ and we added a new service lateral to the existing design.”

These wires are surely not devices — they're not even solid wires. Per 240.2 of the 2005 NEC, a current-limiting overcurrent protective device is “a device that, when interrupting currents in its current-limiting range, reduces the current flowing in the faulted circuit to a magnitude substantially less than that obtainable in the same circuit if the device were replaced with a solid conductor having comparable impedance.”

CONDUCTORS REDUCED TO PAINT COATED PROTECTION

The owner of this facility wouldn't agree to repair this chlorine-damaged conduit, despite the fact that it's located in the pool area and is accessible to guests. There's a good chance the integrity of the ground system has been compromised by this corrosion. The second photo shows how badly deteriorated the remaining portion of the conduit system is in.

Per 300.6(A)(3), “Ferrous metal raceways, cable armor, boxes, cable sheathing, cabinets, elbows, couplings, nipples, fittings, supports, and support hardware shall be permitted to be installed in concrete or in direct contact with the earth, or in areas subject to severe corrosive influences where made of material approved for the condition, or where provided with corrosion protection approved for the condition.”

Found a Code violation? E-mail your photos to Joe Tedesco at electricalinspector@netzero.com.