conduit size ?

[pete379]

I am upgrading my compressor, and will need to run a larger power wire. the
easiest is to use pvc conduit along the wall. I don't know what size is correct.
running 2 #6 thhn and either a #10 or #8 ground any help ?

TIA,pete

 

[41ratrod]

you can run it in 1/2"
if it is a longer run I'd use 3/4"
I have been told to use one size wire smaller for the ground ,but #10 will work.



I'm not a electrician but do stay at Holiday Inn
I have seen doing electrical for meany years.

 

[wyliesdiesels]

I am upgrading my compressor, and will need to run a larger power wire. the
easiest is to use pvc conduit along the wall. I don't know what size is correct.
running 2 #6 thhn and either a #10 or #8 ground any help ?

TIA,pete

The required size of wire depends on the size of the motor. What is the HP rating? Does the manufacturer recommend what size circuit to use or does the compressor come with a cord and plug?

you can run it in 1/2"
if it is a longer run I'd use 3/4"
I have been told to use one size wire smaller for the ground ,but #10 will work.

I'm not a electrician but do stay at Holiday Inn
I have seen doing electrical for meany years.

Huh? What does length have to do with the required size of conduit? And EGC size is based on circuit breaker size NOT 'one size smaller'....

And what the heck does Holidy Inn have to do with this?

 

[pete379]

The required size of wire depends on the size of the motor. What is the HP rating? Does the manufacturer recommend what size circuit to use or does the compressor come with a cord and plug?



Huh? What does length have to do with the required size of conduit? And EGC size is based on circuit breaker size NOT 'one size smaller'....

And what the heck does Holidy Inn have to do with this?

7.5 horse it will be hard wired. I just want to know what size pvc conduit
is correct for 2 #6, and 1 #8
pete

 

[CNGsaves]

As the Sparky's are advising the OP, the size of WIRE is most important so that specific motor on compressor is matched with proper wire. If that wire is planned in PVC conduit over to the subpanel, then it's a "circular" question as need to size wire for motor, then PVC just needs to handle THAT wire (likely 3/4" PVC will be fine, but depends on wire and how many turns, etc). If PVC conduit is all indoors, then Sch 40 is alright, but in direct sunlight then Sch 80 should be used.

These are general guidelines I've been told by electricians, that may need more explanation by location specific sparky in your area - - ie codes vary by country, state, county, and city.

P.S. For WylieDiesel, the Holiday Inn comment by 41RatRod was playing off the commercial that purports that people staying at Holiday Inn Express are "experts" on topics.

 

[LXCam]

OP, you need a 3/4". 1/2" will fit three #8, but its a nightmare to pull. As for Modesto, please forgive him as he wasn't born with a sense of humor.

 

[wyliesdiesels]

7.5 horse it will be hard wired. I just want to know what size pvc conduit
is correct for 2 #6, and 1 #8
pete

Wire for motor circuits is sized at 125%. A 7.5hp motor is listed at 40a, so u can get by with #8 THHN for the hot legs and as long as your breaker is not more than 60a, then #10 THHN will work for the EGC/ground. A 50a breaker should work but can be upsized to 60a if needed to prevent nuisance tripping. I would stick with 3/4" conduit, sch40 will work unless subject to damage...

Does the motor have a starter with an overload relay block?

As the Sparky's are advising the OP, the size of WIRE is most important so that specific motor on compressor is matched with proper wire. If that wire is planned in PVC conduit over to the subpanel, then it's a "circular" question as need to size wire for motor, then PVC just needs to handle THAT wire (likely 1/2" or 3/4" PVC will be fine). If PVC conduit is all indoors, then Sch 40 is alright, but in direct sunlight then Sch 80 should be used.

These are general guidelines I've been told by electricians, that may need more explanation by location specific sparky in your area - - ie codes vary by country, state, county, and city.

P.S. For WylieDiesel, the Holiday Inn comment by 41RatRod was playing off the commercial that purports that people staying at Holiday Inn Express are "experts" on topics.

O ok I get it. Never heard that joke before...

 

[Stuart in MN]

The original poster should mention where they live - if they are not in the US the rules may be different.

 

[mrgm]

3/4" conduit. 1/2" to small. using #6's with #10 gnd on a 7.5hp motor, you will be fine.

 

[pete379]

Wire for motor circuits is sized at 125%. A 7.5hp motor is listed at 40a, so u can get by with #8 THHN for the hot legs and as long as your breaker is not more than 60a, then #10 THHN will work for the EGC/ground. A 50a breaker should work but can be upsized to 60a if needed to prevent nuisance tripping. I would stick with 3/4" conduit, sch40 will work unless subject to damage...

Does the motor have a starter with an overload relay block?.

Thank you ! Yes mag starter installed at factory. I also was considering a disconnect near the compressor. (current compressor is 5hp supplied by
romex #10 , 30a breaker, no disconnect ) approx 58 feet from panel to compressor location.
also I am in Wa. state usually have that showing on most forums !

Once again, Thank you ! pete

 

[wyliesdiesels]

Thank you ! Yes mag starter installed at factory. I also was considering a disconnect near the compressor. (current compressor is 5hp supplied by
romex #10 , 30a breaker, no disconnect ) approx 58 feet from panel to compressor location.
also I am in Wa. state usually have that showing on most forums !

Once again, Thank you ! pete

At that distance, #8 cu wire should be fine. A disconnect would be handy if the compressor doesnt have an on-off switch...

 

[ddawg16]

Personally...I would go 1" on the conduit....

Conduit is like garages....."It's never big enough".....