Jerramundi
Senior Member
- Location
- Chicago
- Occupation
- Licensed Residential Electrician
Question #1) Is an Autotransformer still considered to have (1) Primary Side and (2) Secondary Side since the two coils are no longer isolated?
I want to say NO given that the two portions are wired as a single coil, but then again given that the "Primary Side" and "Secondary Side" taps cover different lengths of this coil, depending on whether you're "bucking or boosting," and thus have different measurable outputs, I lean back towards YES.
Question #2) What Circuit Class, if any, is the "Secondary Side" of a BB Autotransformer?
Technically speaking, the "Secondary Side" circuit is "...supplied from a source that has a rated output of not more than 30V and 1,000VA" (725.41(A)), which would make it a Class I - Power Limited Circuit.
Although when wired as an autotransformer, the output is going to clearly measure more than 30V...
It could also be considered a Class I - Remote Control and Signaling Circuit, as it does not exceed 600V (725.41(B)), although not your typical example
of one (e.g. motor control).
I'm trying to discern the proper classification, if any, because the idea was to run the boosted voltage circuit in an existing conduit with other existing power and light 120V circuits and just want to make sure I'm doing this right.
I want to say NO given that the two portions are wired as a single coil, but then again given that the "Primary Side" and "Secondary Side" taps cover different lengths of this coil, depending on whether you're "bucking or boosting," and thus have different measurable outputs, I lean back towards YES.
Question #2) What Circuit Class, if any, is the "Secondary Side" of a BB Autotransformer?
Technically speaking, the "Secondary Side" circuit is "...supplied from a source that has a rated output of not more than 30V and 1,000VA" (725.41(A)), which would make it a Class I - Power Limited Circuit.
Although when wired as an autotransformer, the output is going to clearly measure more than 30V...
It could also be considered a Class I - Remote Control and Signaling Circuit, as it does not exceed 600V (725.41(B)), although not your typical example
of one (e.g. motor control).
I'm trying to discern the proper classification, if any, because the idea was to run the boosted voltage circuit in an existing conduit with other existing power and light 120V circuits and just want to make sure I'm doing this right.