Silly semantics 415Y/240 or 416Y/240?

[tortuga]

Silly semantics question, I know this does not matter but when doing load calcs for a 416Y/240 system, the transformer namplate says secondary is 416Y/240, however some of the breakers and receptacles use 415Y/240. What is the standard way to describe this system?

Going by simple math when we have 120 * SQRT(3) we get 207.87 and round up to 208V
likewise 277 * SQRT(3) = 479.77

so for a 240 to ground wye system 240 * SQRT(3) we get 415.69, so rounding up its 416V

We don't use 207V on receptacles and 208 on transformers.
So who's right ?

Example of 415V receptacle:

Locking Devices, Twist-Lock®, Insulgrip® Connector, 30A, 4 Pole, 5 Wire Grounding, 240/415 VAC, 3 Phase Y, NEMA L26-30R, Black and white Nylon | HBL2803 | Wiring Device - Kellems

Locking Devices, Twist-Lock®,Insulgrip® Connector, 30A, 4 Pole, 5 Wire Grounding, 240/415 VAC, 3 Phase Y, NEMA L26-30R, Black and white Nylon

www.hubbell.com

Example of 416V transformer

https://www.wolfautomation.com/media/pdf/transformers/hammond/hammond-sentinel-catalog.pdf

 

[wwhitney]

Or:

207 / sqrt(3) = 119.51 round up to 120V
208 / sqrt(3) = 120.09 round down to 120V
415 / sqrt(3) = 239.60 round up to 240V
416 / sqrt(3) = 240.18 round down to 240V

So they are all correct. : - )

Cheers, Wayne

 

[winnie]

It isn't in ANSI C84.1 so you get to make up what you want. I prefer 416/240V

 

[tortuga]

Thanks fellas, so if my continuous + non-continuous sums up to 179723 VA can I use a 250A panel ?

 

[wwhitney]

Thanks fellas, so if my continuous + non-continuous sums up to 179723 VA can I use a 250A panel ?

Certainly under any of the choices, as the worst case is to use 415V * sqrt(3), which gives only 250.03A, and 220.5(B) says we can drop fraction of an amp under 0.5A.

The real question would be if you come up with 180490 VA, then if you use 416V * sqrt(3) you get 250.495A, which rounds down to 250A. But if you use 240V * 3, you get 250.681A, which rounds up to 251A.

Maybe I'll make a proposal to add 416Y/240 to 220.5(A). Edit: Done.

Cheers, Wayne

 

[winnie]

I think you can go all the way up to 180000 VA

Since the whole reason for 416/240 is that nominal 240, I'd use 240 * 250 *3, not 416 * 250 * sqrt(3).

How did you get 179723?????

Jon

 

[tortuga]

Thanks fellas 416 it is.

 

[LarryFine]

I say it's 416v because it's twice 208v. That's also how I remember it.

 

[Joethemechanic]

I've always called it 416, but then in the past couple years I have heard it called 415.