wire-code

dk_6

To all,

I have a honeywell transformer AT150D for the gas steam heat. primary is white and black, the secondary is blue and yellow, I would like to ask how the primary wires connect to 120 ACV, and how the secondary wires connect to the relays and thermostat. Thank you very much.

Timco

Usually a transformer has a special clamp that seats through a 1/2" knock-out in a steel electrical box cover. the wires then connect inside the j-box and the transformer is mounted on the outside. The low voltage wires just run plenum from the transformer to the ZV or whatever you are wiring...

Tim

Rollie Peck_3

Wire code

Hi Dk:

Generally the connections to a small transformer are not critical.

The white primary wire gets connected to the white
neutral supply wire and the black primary wire gets
connected to the black or sometimes red,blue, or other
non-white colored wire.

The color of the secondary wires may be significant
is some particular piece of equipment, but I'm not aware
of any standard arrangement in general wiring. One side
of the transformer secondary should be grounded so that
if the two transformer windings should get shorted
together, a primary fuse or breaker would pop instead of
putting 120 volts on all of the units connected to the
secondary winding.

Rollie Peck

Homeowner

[Deleted User]

just like the primaries,

the secondaries will also have a hot and a neutral. if the paperwork doesn't indicate it, with the trans powered, meter a secondary to ground to determine which is hot