Advantage to 230v single phase vs 115v?

Hi Aaron,
Simple comment and some extra thoughts:

You are right about the lower current draw, and this is the main point. Use the big wire and the higher voltage and there will be a smaller voltage drop along the length of the wire to the tool. When the motor is starting up the current draw is the highest, so a larger voltage drop occurs along the wire. Hence, the full voltage does not arrive at the load. Likewise, when under heavy load on the motor the current required goes up, so again more voltage drop along the wire. So in some respect the issue of using 110 or 220 single phase is determined by how long your run is from the breaker box to the outlet. The longer it is, the more resistance in the wire and so more power goes to the wire instead of to the load. The same effect can happen if you have poor or loose/weak/small connections or bad/loose/underrated outlets.

Have you ever noticed how in some locations when an Air conditioner compressor turns on, the lights in the house dim? It is because of the huge current required to get the compressor motor started and so the large voltage drop along the wires from the power line to the main breaker. Hence, the voltage arriving to all the other circuits dips down and the incandescent lights dim. Usually, bigger lines to the house will solve this issue, but sometimes it is the transformer out on the pole that is too small.

I once had a 1HP air compressor, but where I was using it I only had 15 Amp service. The compressor motor would start fine if there was not load (no compressed air in the tank), but once the tank filled and had shut off, then part of the air was drained, it could not restart because the the startup current load was too high due to the extra difficulty of working against the back pressure in the tank. The current required to start would go well over the 15Amp breaker limit. Motors take a lot more current to get started than to idle or even to run against a normal load. Because of this huge amount of current a stalled motor will soon heat up and burn out!

By the way, there is a legal (code) and safe trick to wiring 220 and 110 from one feeding wire. Use a double pole 220 breaker (both sides of the breaker are coupled mechanically to trip both breakers if either breaker sees its current limit) and run a 3 plus ground wire (say, for 20 amp service, the wire is 12-12-12 gauges plus ground) just as you always would for any 220 circuit. However, at the string of outlet positions you can use either a 220 or a 110 outlet at any location. At a 220 outlet location you wire it up just as you normally would. However, at the 110 outlet position you use a normal 110 outlet and just hook up one side of the the 220 pair and the neutral. The other hot does not need to be used. So the 110 outlets have 110 voltage and the 220 outlets have 220 voltage. In fact, if you purchase good 110 outlets you can break the tab between the two outlets and then the top outlet cam be on one 110 circuit and the bottom outlet can be on the other 110 circuit. You just have to purchase the more expensive wire, but you only have to run one wire and you have the option of voltage at the outlet location. It is safe as the neutral wire is the same size as each of the hot wires. If only one side of the two hot wire's current exceeds the current rating of the breaker both breakers will be tripped. When the 220 is being used the current does not flow in the neutral as it goes down and back the two hot wires. After all, the double pole 220 breaker is really just two 110 breakers mechanically connected to break if either side has current above either breaker rating. If you happen to be drawing power from both the 220 outlet and the 110 outlet, the one side of the wire will be carrying more current, but this is still safe. Say the 220 is using 10 Amps and the 110 is using 10 amps, then back at the breaker one side has 10amp flowing and the other side has 20 amps flowing while the neutral takes care of the imbalanced 10 amps. The total on either side just cannot exceed the breaker 20 Amp limit or it will trip.

What does break most cities' code (not all cities use the same code) is to use two uncoupled 110 breakers in a 220 circuit!

Have fun.

Dave
 
Everyone else has covered the topic well and this is slightly near the dugout but, I'll throw nugget into the air simply because the voltage class gets tossed around so much in everyday life fields, with such variation that it actually may make someone wonder, "What the heck man?"

When it comes to USA -- our voltage class for single phase residential dwellings of today is 120 / 240 volts. It hasn't been 110 volts since probably 1950s. The 230V is seen on many motors simply because we have so many international markets and those single phase motors are shipped the world over. They're used here and they could and are potentially used there --> Britain, UK and all of eastern Europe use 230 volts..its 230 volts line to nuetral (hot to nuetral)..so they get stamped accordingly because of engineer's huddled talk to design components for world power systems.

However, NOW DAYS in the US, our single phase residential power is 120 volts (line to neutral) and 240 volts (line to line) respectively. Quite often, depending on proximity of houses to transformers, the voltage is typically just a tad hotter than 120 or 240. What I'm trying to convey is, its actually quite important to understand that it's not 110 or 115, that would actually signify a voltage drop which could be a potential issue, depending.

Regarding the original question-- anytime you can draw less amperage across your coils inside your motors, you are going to extend the life of your motor simply because you're creating less heat. Less heat equates to a much longer lived motor. Installing those 240 volt outlets is a win-win for you.
 
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I put in 6 outlets at 240v in my shop. I daisy chained them because I only run 1 piece of equipment at a time. I also ran 6ga wire in EMT and a 50 amp breaker. When I moved shops, I took the wiring with me and installed it in the new shop. The hardest part of the job was bending the EMT. Just dont wire anything hot...oh and I never put in for a building permit...but I am cheap that way, I would rather spend money on the wire and outlets. Now I just need to put outlets on the other side of the shop. Tim
 
so one of the things I didn't see in the above postings... dual voltage motors put two sets of windings in series for 120V, and put them in parallel for 240V. You do get a little better starting torque on choosing the 240 volt wiring.
The motor will also run cooler under load, as the current is less in the same gauge wire.

Pro tip: make all 3 of your outlets the same: if your max is 40 A, make them all 40 amp. I made the mistake of having 220V 15A, 20 A, 30 A and 50A in my shop. what a pain!
 
so one of the things I didn't see in the above postings... dual voltage motors put two sets of windings in series for 120V, and put them in parallel for 240V. You do get a little better starting torque on choosing the 240 volt wiring.
The motor will also run cooler under load, as the current is less in the same gauge wire.

Pro tip: make all 3 of your outlets the same: if your max is 40 A, make them all 40 amp. I made the mistake of having 220V 15A, 20 A, 30 A and 50A in my shop. what a pain!

Is this simply in relation to having to keep track of the allowable amps at each outlet or something more subtle. I was thinking of doing 30 amps for most as that seems to cover any of my current / potential needs, with one outside at 40amp for a welder.
 
Is this simply in relation to having to keep track of the allowable amps at each outlet or something more subtle. I was thinking of doing 30 amps for most as that seems to cover any of my current / potential needs, with one outside at 40amp for a welder.
run 40, that is pretty standard and common, you may upgrade equipment someday and may need more power. It is better to run more than you need once than have to rerun power again.
 
If you use the same 40A connector and breakers, you can still run all your lower amperage machines,on them, but allow you to plug anything in anywhere. I now own 3 types of extension cords because I moved most of my machines after wiring (my bad!!)
 
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