Mike Holt

Code Q&A
Q. Is it permissible to install line and load wiring in the same raceway? A. The NEC doesn't restrict the installation of line and load conductors within a common raceway. However, it does prohibit the installation of service conductors within raceway ...
Code Q&A
Q. On a 1,600A 277/480V service, is the neutral conductor from the utility transformer to the service disconnect considered a current carrying conductor if the only line-to-neutral loads is a 200A lighting panel supplying non-linear loads? A. The ...
Code Calculations
Art. 340 covers the use, installation, and construction specifications of service-entrance cable (Types SE and USE). Type SE cable has a flame-retardant, moisture-resistant covering. Type USE cable, identified for underground use, has a ...
Code Quandaries
Stumped by the Code?
Dwelling Unit Feeder/Service Conductor Calculations 2
How do you size conductors for residential services and feeders?
Code Calculations 1
The requirements for protecting the branch-circuit conductors, control apparatus, and circuits that supply hermetic refrigerant motor-compressors against short circuits and ground faults are noted in 440.22. The size and type of short-circuit and ...
Code Q&A
Q. Can a single transfer switch be used to supply both emergency and non-emergency loads, such as a UPS for telecom equipment? A. No, a single transfer switch is not permitted to serve emergency and non-emergency loads . However, a single generator is ...
Code Q&A
Q. Is a disconnecting means for an outdoor spa or hot tub at a single-family dwelling required to be located within sight of the unit? A. Per 680.12 and 680.42, a maintenance disconnecting means shall be installed within sight of spa and hot tub ...
A change to 338.10 of the 2002 NEC
A change to 338.10 of the 2002 NEC is meant to clarify that when Type SE service-entrance cable is used for interior wiring
Don't Get Your Signals Crossed When Installing Radio and TV Equipment
Whether it’s professional transmitting equipment or local ham radio, grounding is the key to a safe system
Code Calculations
The grounding of the grounded (neutral) conductor to earth at service equipment is intended to help the utility limit the voltage imposed by lightning, line surges, or unintentional contact with higher voltage lines by shunting potentially dangerous ...
Code Q&A
Answers to your Code questions.
Code Q&A
Q. If I were to replace a two-wire receptacle in a bathroom outlet that doesn't have a grounding means, am I required to replace it with a GFCI receptacle? A. No, the replacement receptacle isn’t required to be of the GFCI type. However, it’s required ...
Don't Let Voltage Drop Get Your System Down
Contrary to common belief, the NEC generally doesn't require you to size conductors to accommodate voltage drop. It merely suggests in the Fine Print
Code Q&A
The answers to your NEC quandaries
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