Stop Voltage drop

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Frank DuVal

Senior Member
Location
Fredericksburg, VA 21 Hours from Winged Horses wi
Occupation
Electrical Contractor, Electrical Engineer
Open that grounded phase conductor and you now have full ?? voltage on the equipment at the detached building site.
How, there is a transformer in the circuit, not an auto transformer, so when the grounded conductor is opened, the transformer quits working. No output. How much capacitive coupling between windings is there?

I do not see high voltage on my house if the power company loses the neutral to their step down transformer, do I?
 

kwired

Electron manager
Location
NE Nebraska
Open the grounded conductor between the two transformers. You will have an open circuit voltage of 600v. That will raise voltage, referenced to earth, on the bonded equipment at the Detached structure.
I agree.
How, there is a transformer in the circuit, not an auto transformer, so when the grounded conductor is opened, the transformer quits working. No output. How much capacitive coupling between windings is there?

I do not see high voltage on my house if the power company loses the neutral to their step down transformer, do I?
usually not, but depending on where it is lost and what is connected to each side of the "break" it is possible. Grounding electrodes on the secondary will typically carry enough current at the high voltage that earth return will allow enough current for primary winding to function, you still likely to see some voltage rise on non current carrying bonded objects over earth ground.
 

paulengr

Senior Member
Well anything less than 1/0 cannot be ran in parallel correct?
I think just picking a comfortable amperage that’s owner will want up there and derating the breaker is going to be our best option for this project. Thank you for all the info on the topic though guys!!

In most cases, yes. I see often where flexible cord loads use parallel conductors. I don’t recall a lower limit. It’s just that in most cases paralleling say #14 would be silly and not economical,
 

kwired

Electron manager
Location
NE Nebraska
In most cases, yes. I see often where flexible cord loads use parallel conductors. I don’t recall a lower limit. It’s just that in most cases paralleling say #14 would be silly and not economical,
I doubt the economics have anything to do with why NEC requires 1/0 or larger as the general rule for parallel conductors, this is concerning using multiple conductors in parallel to effectively create an effectively larger conductor for current carrying capacity reasons. There might be other reasons to connect conductors in parallel that don't have to meet this rule, like control switches and their connecting conductors wired in parallel to create an "or logic function" in the control scheme.
 

Electricmo

Senior Member
Location
Missouri
Occupation
Lineman
The OP never stated what size wire he is running. Voltage drop calculations are in 1000’ increments. With the stated load he can run 2/0 aluminum or 1/0 copper. Aluminum would be much more economical. Hell1/0 aluminum would most likely work till the customer starts adding load like they always do.
 

Cow

Senior Member
Location
Eastern Oregon
Occupation
Electrician
Aluminum cablecon.

At this distance and with the load you mentioned, this will be the cheapest method in my opinion. Finding a source to purchase it from, may be more difficult for you. Where I'm at, if I stick to a few common sizes, I can have it cut to length within a couple days usually.
 
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