Neutral Draw 37-42 amps ?

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i have a service on a high leg 208Y three phase service that draws 37 to 42 amps
is this normal ?
Also the wires that come in to the top side of the main disconnect ( Three 200 Amp fuse) are extremely HOT ( temp ) and
can not be touched. L1 is 120-166 amps L2 is 98-110 amps L3 is 120-171 amps.
the bottom wires to the the panels in the inside are hot ( temp ) but able to be touched
 

augie47

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A 208Y system would not have a high leg.
I didn't do the math, but based on your phase currents, the neutral current looks fine.
Without knowing the wire sizes one can not determine if they are overloaded, but if the wire sizes on the top and bottom of your disconnect are equal, I would be highly suspicious of a loose connection.
 

ptonsparky

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You not supposed to touch them...they are hot.




Which one of the phases is the high leg?
What is the three phase load? Amperage of hi leg.
Subtracting this from the current of other two will tell you the single phase load.
The difference of the two single phase currents will give you the approximate neutral current.


Offhand I would say you have failed connections at your disconnect. Line, load, internal or all of them.

What size are the wires?
 

ptonsparky

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NE (9.06 miles @5.9 Degrees from Winged Horses)
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Electrical Contractor
A 208Y system would not have a high leg.
I didn't do the math, but based on your phase currents, the neutral current looks fine.
Without knowing the wire sizes one can not determine if they are overloaded, but if the wire sizes on the top and bottom of your disconnect are equal, I would be highly suspicious of a loose connection.
I missed where he said 'y'. Minor detail but it does make the neutral calc a bit more involved. Now if he has 208 v to N on one of the legs and it is a delta. Im good.
 

infinity

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i have a service on a high leg 208Y three phase service that draws 37 to 42 amps
is this normal ?

So you need to clarify is this a 3?, 4W Delta (high leg) or a WYE service? Also if it's a WYE what type of meter to you use to read the neutral current. If harmonics are present you would need a True-RMS type meter to get an accurate neutral current reading.
 

Part-Time

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Location
Houston, Texas
Phase ONE is 120v 3/0, Phase TWO is 208v ( center ) 1/0 Phase THREE 120v 3/0 Neutral is 1/0
Also the Wire Temperature exceeds 268 Degrees Fahrenheit
4 wire service
 
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ptonsparky

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NE (9.06 miles @5.9 Degrees from Winged Horses)
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Electrical Contractor
Phase ONE is 120v 3/0, Phase TWO is 208v ( center ) 1/0 Phase THREE 120v 3/0 Neutral is 1/0
Also the Wire Temperature exceeds 268 Degrees Fahrenheit
4 wire service
See post #3.

Guessing you have a 200 amp service that is at capacity or above. Replace the service with properly sized equipment.

Trying to calculate the neutral current by moving one clamp-on from wire to wire is pretty difficult with a constantly changing load. Clamping the 2 120v conductors at the same time should give you the current on the neutral. You would still need to meter the neutral to compare. Next step is to buy equipment designed for what you want to do. $3000 give or take. Small detail.
 

jim dungar

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Wisconsin
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Phase ONE is 120v 3/0, Phase TWO is 208v ( center ) 1/0 Phase THREE 120v 3/0 Neutral is 1/0
Also the Wire Temperature exceeds 268 Degrees Fahrenheit
4 wire service

Per ANSI standards what you have is called a 240/120V (3-phase 4-wire system).
Per most utility references it is called a 120/240V #-phase system.

The most common industry slang calls this a Wild-leg, or High-leg, or a center-tapped delta.

Do you know if your service is a closed or an open delta?
 
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