> And remember that it is NOT OK (and is
> illegal) to run a
> 120V load between one side of the line and ground. Indeed,
> putting load
> current on ground is a recipe for hum pickup.
Which is why if there is ever a chance that you might need both 120 and 240
in the same piece of equipment, run a 4-wire branch circuit (two hots,
neutral, EGC) and use a 4-wire receptacle like a L14-20 twistlock.
> And bonding neutral to ground is even worse.
Although a little different than the instant case, there are some situations
where NEC not only allows but requires that you to bond neutral to the
chassis of an appliance as a substitute for a separate EGC whre one doesn't
exist. Electric dryers, ranges, and ovens come to mind. The difference,
however, is that in these situations there are two hot legs plus a neutral
conductor (which has to be insulated, not bare), not two hots plus an EGC.
Regardless of what NEC says, it's still not a very good idea, as once the
neutral is bonded to the chassis, if there happens to be some other
conductive path from the frame to ground, such as through incidental contact
with a water pipe or another appliance with a proper frame ground, it
creates a new, undesired, path for current flow from the load to ground.
> 73, Jim K9YC
--- Jeff WN3A
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