208/1 phase neutral

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cwb333 said:
Why, when running a 208/1 phase line, do you need a neutral sometimes and sometimes you don't?
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I don't understand your question. The only time you would need a neutral run with a circuit would be if the load required a line to neutral connection.

For example a dryer circuit is a multiwire branch circuit that has both a 240 volt line to line load and a 120 volt line to neutral load. That is why we provide a neutral conductor with the branch circuit to the dryer.

Does this help?

Chris
 
As Chris said, it would depend on if the load were just L-L such as a single motor, or if it were a L-N-L load such as a range or a dryer.

Roger
 
cwb333 said:
Why, when running a 208/1 phase line, do you need a neutral sometimes and sometimes you don't?
Click to expand...

208V is the result of the line-to-line voltage between two phases of a three phase 208/120V system. If you need andother voltage at the user point, and it is 120V then you could run a third wire, the grounded neutral, for that purpose and the three wires will be your current carrying conductors. You can use this scheme only if it is the same equipment and it is designed to be used on a two phase/three wire system. Ex. you should not combine an electric dryer(208) with a washer(120), should the washer have a heat-up feature. The common phase OCPD may be overloaded.
 
Look at the nameplate of whatever you're hooking up. If it says 208volts, then no neutral is needed. If it states 120/208 or 208/120, then one is required.

No offence, buy why is someone who has been in the trade 40 years asking something so basic?
 
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