In 720, systems operating at less than 50 volts, it says: "720.5 Lampholders. Standard lampholders that have a rating of not less than 660 watts shall be used."What does "standard" mean? Does it include the many different bases (ie regular, edison, mr16, etc.) Many listed luminaires use lampholders (usually in the smaller base types) which are not rated for 660 watts. Are they out? I am building a DC cabin off the grid and need some guidance on this question.
Low voltage nec 720.5
- Thread starter Dave Eng
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- Bremerton, Washington
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- Master Electrician
First, the title of Art 720 is not low voltage. When you mention low voltage most think this is a system that has no hazard. But it has a high current at 36 or so volts, but DC, so there is a fire hazardThis article dates from the 1930s when DC power plants were used on farms. We have to look at what type lampholders were available then, the standard type would be the edison for a common lamp. All the other types you mention were not invented then.
Do a google for Delco Farm Plants...
Do a google for Delco Farm Plants...
Thanks, Tom, I should not have referred to it as Low Voltage. It is a stand-alone 12v PV system. Are you saying that this provision is some sort of arcane reference that should have been purged? Still, I may have to deal with an inspector looking for these lampholders. Some household type Luminaires are OK with DC, but most (though not all) DC bulbs do not have standard bases.
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