Autotransformer

[RumRunner]

Hi, a rookie to this forum. . . pardon if I'm on the wrong path.

I came across a provision in the 1991 NEC (LA City Electrical Code) that disallows auto transformers in motor homes or RV Parks in general. RV owners call this and even manufactures “Auto former” which is basically an auto transformer capable of having a selectable taps either manually or automatically.



In that particular article it simply state some sort of “anecdotal” statement which doesn't explain much.


Can anyone elaborate or some kind of discernible reason for this.


My thinking leads me to assume that this is similar to having solar panels which store energy that could pose hazard to utility workers.


This topic has been hotly debated in forums for Rvers and park owners.


Thanks.

 

[GoldDigger]

Not a clue!

There is nothing inherently unsafe, IMHO, in wiring in an autotransformer for voltage correction.
However is the need for voltage correction in the first place is excessive voltage drop in the RV park wiring, then it will make the energy loss slightly worse since the RV loads may draw even more current through the park fixed wiring. It would be putting a bandaid on a problem that should be fixed by the park.

Neither a solar PV system nor an autotransformer "store" energy in any significant way.

The PV system, IF the rather through and UL-tested anti-islanding mechanisms in the grid interactive inverter fail there is a chance that it would put normal operating voltages on wiring within the park and back to POCO that was expected to be dead. This is considered to be so unlikely as not to require additional precautions.
An autotransformer, like any transformer, can store energy in its magnetic field for a portion of each voltage cycle. This is also not considered to be a hazard.