How to test a Delta 120/240 (Wild Leg) 3 phase electrical system , explained!!

3 phase Delta 120/240 volt system.

I’m new to YouTube. Everyday I watch videos of how to, or how do you?....etc. I am a hands on type of guy and every day I am working on something different. So I figured that maybe if I start posting some of what I run into in may help someone else with what they are doing as the videos I have watch helped me throughout the years.

I apologize for the lack of my experience making videos. In time I am sure they will get better. If I make any mistakes or misleads please comment down below and bring it to my intention. Also if you have any advice or suggestions I would love to hear them.

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[Sparky-wwre]

NEC 110.15 requires the high leg be marked orange, or other effective means, so in theory it could be red, I've heard old timers referring to this as red leg delta. NEC 408.3 (E) (1) requires the high leg to be on the B phase, in Panelboards. NEC 408.3 (F) (1) requires such a panelboard be field marked with CAUTION: ___ PHASE HAS ___ VOLTS TO GROUND. in most cases that will be 208. In very rare installations you will see a 240/480 volt 3ø 4 wire system, in this case the high leg is 415 volts to ground.

Installations before 1975, typically have the high leg on phase C. And a common (and very expensive) mistake is to accidentally connect a single pole breaker to the high leg and destroy everything on that circuit. Having said all this, it's crucial to verify the voltages with a suitable meter, never rely on colors.

[JB-Brack]

Quick and to the point. Love it!
I subscribed.

[charlespaine]

Simplify show in a circuit drawing form it is easier to understand

[Calicostring]

The high leg is NOT "220" or "240" to neutral.
With exactly 120v on the other phases, the high-leg would be (should be) 208v. Of course, variations in primary voltage due to loading, etc., and variations in the transformers themselves can cause higher or lower actual voltages. But on a 3ph 240v hi-leg system, the high leg is 208v (do the math).

[galagatron]

Why when you do either a or b leg to the high leg c you don't get 120 plus 240 equals 360?

[mauriciocorona]

With all due respect bud…. High leg or wild leg to neutral/ ground should be 208v, not 220v or 240v.

[jackieg]

Dude your not right with everything you said

[geoffreygraham]

It's called a 208 system cause it's got a 208 leg. Lol