Hello! new to this forum. read through some topics and great forum!
I recently took over a woodshop and im just replacing the heavy woodworking machineries. so I need to install some 220V lines.
right now, I only have
-220V 15A line
What I need is, to install following breakers(with the distance from the breaker box and my guess of AWG for the line)
-240V 40A line for planer(240V 30A the manual says to use 40A breaker) –a little over 50′ — 8AWG needed?
-240V 40A line for compressor(240V 30A) –about 65′ — 8AWG?
-240V 15A line for table saw(220V 12A) –about 65′ –10AWG?
-240V 15A line for Dust Collector(240V 7.8A) –about 55′ –10AWG?
could you let me know if this is right? also, if I put the 60A breaker for Dust Collector and Compressor, I can split the line so I dont need to put an extra?
also someone mentioned that table saw is 12A but just in case, should be 20A breaker. is that right? or i can use 15A?
another thing is AWG for the machines. as I mentioned the distance from the box, they are little over 50′ so I should get bigger wire?
i know this is very dangerous to do it alone so im trying to get hold of an electrician but I did my homework and it would be great if i can save $. if you have better ideas, please let me know.
any inputs would be great.
Thank you so much for reading this!
Replies
There are several "calculators" online which, given an amperage and a distance, will tell you what size wire is required to achieve a given max voltage drop.
What you neeed to do, for each piece of equipment, is determine what the RUN current is (not simply the nameplate current, which essentially is the required breaker size) and what the minimum input voltage is. Plus you need to know your local line voltage (at the breaker panel, with "average" load). From that you can calculate the required wire sizes.
Even though you may oversize the wiring, DO NOT oversize the breakers for your larger pieces of equipment -- the breaker needs to be the right size to do its job.
thank you so much for reply.
i will look for the calculater for distance.
thanx!
You really sound like you are at least one wire size bigger than you have to be. These are motor loads so the wire gets sized to the name plate full load current (FLA) and the breaker gets sized to handle the starting current. (up tp 250% of the FLA)
I would be skeptical about a 60a for two 30a loads. I bet the manufacturer instructions do not allow it . I doubt it is a serious safety issue tho. The NEC rule is you size the wire to 125% of the biggest load and 100% of the other one. A 60a breaker will never start both of them at the same time. (like a power glitch)
thank you for your reply.
i think i will run each machines with its own line then.
thank you!
you are right, ive tried several online calculator for wire size and i think i was going one size bigger than necessary.
table saw 12awg
planer 10awg
dust collector 12awg
compressor might be 8awg
thanx!
Will you be the only one operating machines in the shop? If so, it's likely that only one machine will be running at any given time. You could factor this into your calculations. Or not. But it's worth considering.
Well, obviously the collector runs when the saw or planer runs, and the compressor can kick on at any time. The saw and planer likely would never run at the same time, though.