Hello:
Was wondering about the service wires running along my street (live outside of Boston)
a. There are 3, typically, so I guess the main service on the street is 3 Phase. Right?
b. If so, what voltage do they typically run, phase to phase; I believe it's about 13,000 V phase to phase, but am not sure ?
c. What would it be phase to Neutral ?
d. Then, it seems, they tap off of a phase with a single wire going to a pole mounted transformer every half block or so that services a "few" houses. For "balance", I believe, but am not sure, that they (probably) tap off of a different phase further down the block. Correct ?
This is what confuses me:
The secondary of the transformer seems to consist of three wires which are eventually brought into the house: this being 220V and a ground. I imagine that this is just the transformer secondary wiring with a center tap for the ground.
Right ?
What I can't figure out is If the tap off the high voltage (one of the 13K phases) to the transformer primary is a single wire, which it seems to be, where is the second wire for the primary winding ?
Is it wound as an "auto-transformer" with the return leg of the primary wired directly to the secondary wiring inside the transformer, or is it wired internally to the secondary's center tap, presumably the ground, and uses that ?
If anyone can clarify all of this a bit for me, would be most appreciative. I looked on the web, but couldn't find any appropriate drawings or explanations. Are there any ?
Thanks, Bob