Submeter for 3 phase high leg delta

Location
Portland, OR
Occupation
Electrical Contractor
Anyone have any experience with installing submeters on a high leg delta service? Seems that most submeters cater to 120/208 wye and 277/480 wye, especially the common Leviton ones I've used in the past. Any product recommendations?
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
Anyone have any experience with installing submeters on a high leg delta service? Seems that most submeters cater to 120/208 wye and 277/480 wye, especially the common Leviton ones I've used in the past. Any product recommendations?
If the meter has connections to all three hot lines and the neutral, it might simply work properly on a high leg delta.
 

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
Retired Electrical Engineer - Power Systems
If the meter has connections to all three hot lines and the neutral, it might simply work properly on a high leg delta.
No it will not. The meter needs to have a setting for the center tapped delta, other wise it thinks the neutral connection creates a wye point.

A high leg delta is a fairly occasional meter request in the US so low end products, from overseas, may not support it.
 

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
My _guess_ is that it depends upon how 'smart' the meter is trying to be.

If you have a meter that simply measures instantaneous V*I separately for each of 3 phases, then a meter 'designed' for grounded wye use will correctly meter on a high leg delta system with grounded neutral. The natural way such a meter works will automatically compensate for the phase angle and voltage differences between the two systems, because the meter doesn't actually care about them; all it cares about is the power delivered which is integrated instantaneous V*I.

A grounded neutral high leg delta is essentially a very unbalanced wye system.

But if the meter is designed with too much smarts, a meter designed for balanced wye usage might recognize and treat as an error a high leg delta system.

-Jon
 
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