Electrical question
- Thread starter Bugeye
- Start date
SnapsProvolone
Well-Known Member
Your breaker will trip at 80%. So a 30 amp gives 24 usable amps.
Voltage drop with #8 copper will be just below 3%. Stick with #8 and 40 amp ocpd.
Sand4x105
Well-Known Member
WTF... NO-No-No...
Use #6...
Use a 30 amp breaker...
Don't worry about it...
You can, and should always on a long run, just for safety up size your wire..
When you upsize, you do not also need to up size your breaker...
And No.... Your breaker will not blow at 80% of load... that's bull shit....
Breakers are engineered to with stand 125% of load for a short time...
If your load will always be less than 24 amps like snaps says 80 % of max...
You want 30 amps... use a 30 amp breaker...
or
You want 40 amps... use a 40 amp breaker...
or...
You want 50 amps... use a 50 amp breaker...
Use bigger wire then your options will be better...
You can hook up 500 MCM to a 20 amp breaker [ok adapt it]....
Run it a couple of thousand feet... and still have 20 amps out on the end of your wire....
Never hook up a smaller sized wire to a breaker than you should...
But a larger sized wire to a breaker... totally OK..Legal, and very safe...
Good Luck man....
Use #6...
Use a 30 amp breaker...
Don't worry about it...
You can, and should always on a long run, just for safety up size your wire..
When you upsize, you do not also need to up size your breaker...
And No.... Your breaker will not blow at 80% of load... that's bull shit....
Breakers are engineered to with stand 125% of load for a short time...
If your load will always be less than 24 amps like snaps says 80 % of max...
You want 30 amps... use a 30 amp breaker...
or
You want 40 amps... use a 40 amp breaker...
or...
You want 50 amps... use a 50 amp breaker...
Use bigger wire then your options will be better...
You can hook up 500 MCM to a 20 amp breaker [ok adapt it]....
Run it a couple of thousand feet... and still have 20 amps out on the end of your wire....
Never hook up a smaller sized wire to a breaker than you should...
But a larger sized wire to a breaker... totally OK..Legal, and very safe...
Good Luck man....
SnapsProvolone
Well-Known Member
#6 is overkill imho. His vdrop with #8 cu at 200' / 24 amps / 240 volts is 2.77%.
Sand4x105
Well-Known Member
OVERKILL... maybe...
Have you ever heard of a new grower possibly expanding their grow in the future?
I'm just thinking "AHEAD" for him...
For the small price of wire... [labor/time] same...
He can protect him self from the future, and a double the size of his grow room down the road...
I live in the future...
He'll need the extra room...
I have a crystal ball....
Sand4x105
Well-Known Member
as I said... You can run bigger wire any time you want and it will be better....
Use #10 for a 30 amp breaker... that's code...
If you want to do more than the "Minimum" required by code it's fine...
Snaps recommends the minimum...
I recommend you oversize your wire...
There is no wrong...
Snaps way is cheaper, but correct...
My way is better, and protects you in the future...
And better than correct...
I was a EC in CA for 25+ years...
It is common practice to up size wire for longer runs...
I'd up size every circuit that was over 100'... not by code, but because it was better than code...
Code is just the minimum required....
You decide...
Use #10 for a 30 amp breaker... that's code...
If you want to do more than the "Minimum" required by code it's fine...
Snaps recommends the minimum...
I recommend you oversize your wire...
There is no wrong...
Snaps way is cheaper, but correct...
My way is better, and protects you in the future...
And better than correct...
I was a EC in CA for 25+ years...
It is common practice to up size wire for longer runs...
I'd up size every circuit that was over 100'... not by code, but because it was better than code...
Code is just the minimum required....
You decide...
SnapsProvolone
Well-Known Member
If it's a detached structure, by NEC if applicable, you are limited to one 3 wire feed.
SnapsProvolone
Well-Known Member
It never hurts to plan ahead. Only bugger is existing underground raceway diameter. Fill calcs and the like.
green217
Well-Known Member
I'm a electrician with 15 years exp., you should go with the bigger wire if your run is 200'. There will be a voltage drop! you can google a chart that will tell you how much you lose per ft. for what ever size wire. find that chart.
That is if you are going to be pulling anywhere close to the 30 amps.
here's a link to a voltage drop calculator. http://www.calculator.net/voltage-drop-calculator.html
I ran a 200' peice of 10 awg copper and it said you'd only lose 7 volts out of 120 alittle over 6 percent. Not as bad as i thought, i wouldn't worry about it on second thought.
That is if you are going to be pulling anywhere close to the 30 amps.
here's a link to a voltage drop calculator. http://www.calculator.net/voltage-drop-calculator.html
I ran a 200' peice of 10 awg copper and it said you'd only lose 7 volts out of 120 alittle over 6 percent. Not as bad as i thought, i wouldn't worry about it on second thought.
Ou8aCracker2
Well-Known Member
If you have a 30amp breaker and plug a heater or any electrical device thst uses 30amps then you will trip that breaker everytime.
When running a continuous load (any load that runs 3 hours or longer) you can only use up to 80% of that breakers ampacity!
So the ampacity you could safely run on a 30amp breaker is 24amps
30 x .8 = 24
24amps x 110v = 2640w