Mixed Gauge on a Long Run

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JHZR2

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Situation is that there is a long run of conductor, feeding an 18-19A load for a portable 120V air compressor that gets moved around. Currently is a 20A Eaton CH breaker protecting 12ga to receptacle, then 10ga from the receptacle into the compressor. Compressor runs suitably, but overall conductor length results in voltage at motor being a little bit lower than I'd like. Would like to upgrade the conductor from the panel to the receptacle, but the receptacle has a run through a wall and a few other reasons that Id prefer to not pull conductor through. Instead, Id like to make a junction in a simple, accessible, exposed location (in the basement), to connect the 10ga run to the remnant 12ga to the receptacle. This would result in maybe 2ft of 12ga in the run.

So were talking about turning it into the following:

Breaker - 10ga (25ft) - junction - 12ga (2ft) - receptacle - 10ga (60ft) - load

We could run the calculations and see that a foot or two of 12ga conductor adds miniscule voltage drop and heating. But are there other practical reasons why this should be avoided?

The compressor sees very sporadic use, requires some mobility, and hard wiring it in place with one continuous 10ga run is not in play here.

Thanks!
 
Why do they drag the compressor around with that long cord instead of just running their air hose to where the work is? Compressors are happier on short cordsets. Ears are happier too, when they're far from a compressor...
 
Craigv said:
Why do they drag the compressor around with that long cord instead of just running their air hose to where the work is? Compressors are happier on short cordsets. Ears are happier too, when they're far from a compressor...
Click to expand...
Good suggestion. Depending on amount of air flow one still may need to increase size of hose to get desired flow and pressure - so it sort of comes down to larger wire vs larger hose and the advantages/disadvantages of each.
 
Craigv said:
Why do they drag the compressor around with that long cord instead of just running their air hose to where the work is? Compressors are happier on short cordsets. Ears are happier too, when they're far from a compressor...
Click to expand...


Have to agree with this, at home I run better then 200' of hose to another house on the property undergoing renovation, the shop compressor is a 5 HP 2 stage with a cast iron pump, so it gives me all the air I want & a whole lot quieter then any portable compressor even near the 5 HP.
 
kwired said:
Good suggestion. Depending on amount of air flow one still may need to increase size of hose to get desired flow and pressure - so it sort of comes down to larger wire vs larger hose and the advantages/disadvantages of each.
Click to expand...

You'd be trading voltage drop for pressure drop, of course. Yes, run the numbers.
 
Air runs have the same analogous issues (pressure drop and flow considerations) as electrons.

Its a hobby garage and things get moved around, nothing is regularly used. There is some hard plumbing for air, so the situation as it is set up works.

Ideally a full 10ga underground run would be used back to the panel. Since it would require digging up yards, paver patio and driveway, the setup as it stands is ideal.

Just wanted to verify there wasnt a practical reasoning against the intermediate low gauge section. It's easy to run voltage drop calculations, but I was really looking for other unforeseen reasons against doing it.
 
JHZR2 said:
Air runs have the same analogous issues (pressure drop and flow considerations) as electrons.
Click to expand...

Pneumatic systems behave somewhat similarly, but for practical purposes you'll never see a flow problem caused by inadequate hose diameter over the distances we're discussing. For all intents and purposes, if the hose is of adequate diameter for a 20' length, it'll be just fine for 60' too. And for such a small compressor, it's unlikely you'll ever have a tool it can run properly yet require a hose diameter that would be unwieldy. But of course, if what you're doing now works, there's no need to change it for a hobby shop.
 
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