110v, 115v, 120v - Electricians and/or EE's Does it matter?

[Joe A Faulkner]

I'm hoping someone can shed some light on "voltage" ratings for outlets, switches and appliances. I've read that for all practical considerations, that an outlet or switch rated at 110v 20 amp, versus 115v 20 amp, versus 120v 20 amp are equivalent. Such that if you install outlets that are rated 110v 20 amp, you are safe to use them to power motors spec'd at 120v 20 amp.

[David Helm]

It's my understanding that all outlets are 120 volt or 240 volt and that 110 is just a laypersons number. You are definitely safe using a 120v 20 amp.

[Dan Hintz]

Technically, what is supposed to be at every outlet in your house is 120V. Once you take into account resistive losses, long line lengths, etc. it can vary a bit once it makes it to your house (particularly if you're far away from the main grid). You'll see mention of 110V, 115V, and so on, and many people may actually measure something similar at their wall, but it's designed to be 120V (and 240V when used across both phases, not the 210V, 220V, etc. you often see).

So, with that in mind, most things will work just fine on 110V, even if it was designed to run off of 120V. Electronics are downconverted to 12V, 5V, etc., so a little less at the high end is irrelevant. Motors, on the other hand, prefer to run at the voltage they were designed for. Running at a lower voltage increases the heat from the windings, so you want to watch the line from getting too low. Old refrigerators, well pumps, etc. can be victims of this. Newer equipment can often be controlled indirectly by microprocessors that handle variances in the line voltage, so they're somewhat safe to use on the lower voltages.

[ray hampton]

105 ,110 ,115,120,125 volts do make a different when apply to a lamp bulb a high voltage will cause the bulb to be extra bright, the older transformer were rated for a lower voltage if I not mistaken

[Nick Lazz]

What Dan said...also depending on where you live voltage varies. If you live out in the sticks it is likely at the higher end.
I am not an electrician, but I play one from time to time...

[John Gomes]

In a less than perfecxt world, ten per cent up or down should be okay on voltage. What I've been finding a lot of lately are cheap capaciters that just don't last. A capacitor not living up to it's rating can reak havoc, hot motor, burnout, etc.

[Van Huskey]

110V is a legacy term left over from ages gone by
115V comes from the design side, equipment is normally designed to run on 115V +/- 10%
120V comes from the supply side, under standard conditions electrical utilities deleiver electricity at 120V +/- 5%

In the end for us the numbers mean the same thing, just as 220/230/240 mean the same thing BUT 208V does NOT.

[Curt Harms]

What Dan said...also depending on where you live voltage varies. If you live out in the sticks it is likely at the higher end.
I am not an electrician, but I play one from time to time...
Higher voltage is not just in remote areas. Where I live I can see the steam from exhausted neutrons at the Limerick nuke plant. The times I've checked line voltage - generally during hot spells with high air conditioning loads we run 124/248 volts. Just speculating here - no a sparky pro of any description - but I'm guessing they run as high as they can get by with to keep line & transformer temps down or capacity up? Higher volts require less amps to transport the same number of watts? We haven't had any electrical problems in the 16 years we've lived here so I'm not complaining.

[Joe A Faulkner]

My question was motivated by a discussion in another thread regarding remote control units for DC's. The OP asked about remote control units rated for 120v 20 amp. I suggested the iVac Pro which is rated at 115v 20 amp https://www.mbrightonline.com/ecommerce.action?ecategoryid=9.

The OP is concerned that since this module is not rated 120v 20 amp, it would not be up to snuff. My thought was that for this application the 115v 20 amp rating is essentially the same as a 120v 20 amp rating.

In many respects it is kind of a mute point as it relates to the OP, since the manufacturer now is stating that anyone running 1.5 HP or more should use a contactor in conjunction with the switch (use the switch to turn on the contactor). But still I thought it would be good to hear from those who understand this topic a little bit better about the appreciable difference between the ratings. I note that Leviton's 20 amp outlets are now rated at 125v.

[ray hampton]

I forgot what my actual voltage are suppose to be but the multimeter read my voltage at 127 if I recall right, the electric company assume me that my voltage are okay

[Dan Case LR]

The voltage on commercial electrical power lines fluctuates, depending on the load. There are some loads--big motors, for example--that draw substantially more current when starting up than when running. Back in the early days of my career as a broadcast engineer, I worked at a high-power UHF TV station. When we fired up the big power supplies (the beam supplies for big klystron tubes), the fluorescent lights all over the building would go out for a fraction of a second.

The nominal voltage of electrical service--120/240 in the US--is the average voltage over time. Depending on whose set of standards you look at, the voltage could vary as much as +5% -13%. Properly designed electrical equipment is designed to deal with those variances. The NEMA (National Electrical Manufacturer's association) standard calls for electrical appliances and equipment to be designed to operate between -10% and +10% of nominal nameplate voltage. A motor with a nameplate rating of 115 volts is therefore designed to operate between 103.5 and 126.5 volts.

Bottom line: don't worry about it.

D.

[Dan Hintz]

Dan,

Those huge supplies are scary pieces of equipment. When I worked for a telecommunications consulting firm, the owner's son was out on a field call from a client with an AM tower. He didn't know the gate around the tower was there for a reason, so he put his hand out to lean on the tower. Needless to say, the spark that shot out of the tower did a bit of damage to his finger and made sure he never did that again.

[Dan Case LR]

Dan,

Those huge supplies are scary pieces of equipment. When I worked for a telecommunications consulting firm, the owner's son was out on a field call from a client with an AM tower. He didn't know the gate around the tower was there for a reason, so he put his hand out to lean on the tower. Needless to say, the spark that shot out of the tower did a bit of damage to his finger and made sure he never did that again.

He was a lucky guy. RF energy burns from the inside out and the burns can be particularly painful. I've been bitten by a few AM's over the years. At lower power levels, it's seriously unpleasant. At higher power levels, it can be seriously life-shortening.

D.

[Bob Landel]

Joe, I think you have shown me the way! It appears the surge of my dust collector starting, as well as high amp output while running, causes the plug connection between my dust collector and the remote control unit to be welded together! (I am still awaiting receiving a amp meter to confirm my dust collector motor's output.)

It looks like the answer is to install a relay switch (contactor) between the dust collector and remote control. Yes, I know it is more expensive. It should solve my welding problem and having to replace remotes every so often.

Nice to see IVac has added a remote controller. I may want to go their components the whole way.

What does OP mean?



My question was motivated by a discussion in another thread regarding remote control units for DC's. The OP asked about remote control units rated for 120v 20 amp. I suggested the iVac Pro which is rated at 115v 20 amp https://www.mbrightonline.com/ecommerce.action?ecategoryid=9.

The OP is concerned that since this module is not rated 120v 20 amp, it would not be up to snuff. My thought was that for this application the 115v 20 amp rating is essentially the same as a 120v 20 amp rating.

In many respects it is kind of a mute point as it relates to the OP, since the manufacturer now is stating that anyone running 1.5 HP or more should use a contactor in conjunction with the switch (use the switch to turn on the contactor). But still I thought it would be good to hear from those who understand this topic a little bit better about the appreciable difference between the ratings. I note that Leviton's 20 amp outlets are now rated at 125v.

[Michael O'Neill]

220 ,221 What ever it takes........ Michael Keaton Mr Mom.........

[Dan Hintz]

220 ,221 What ever it takes........ Michael Keaton Mr Mom.........
Love that show, and I quote that one often...

[Joe A Faulkner]

Bob, I think we found the way together. When you questioned the the voltage rating it motivated me to ask others for more information. Something I love about this forum is the wealth of info.

OP is shorthand for "original post" or "original poster", meaning the person who started the post or thread. Of course sometimes there is conflicting information, and there almost always is more than one way to skin a cat. Good luck in getting your remote control solution worked out. One thing to consider no matter what solution you go with. In general, I'm not sure it is a great idea to cycle your DC on and off again in short succession. So if you have a series of cuts to make with brief pauses between cuts, you should probably just fire up the DC and let it run. With iVac modules you can do this by flipping a switch. If you use a remote to fire a contactor then you are basically starting the DC independently of your tools and you wouldn't necessarily want or need the iTool module.

[Bob Landel]

Joe, just read your newest response. Finally got a amp meter and tested my Delta 1 1/2 hp dust collector. While it was in spec., you're right about cycling on and off putting a strain on the system; including the remote control unit. My DC started up pulling 67amps!, then quickly settled down to 14.1 to 14.7 amps on a steady run. However, I just don't like the noise running it while it is not being used so I do cycle.

Multi tool units of the IVac Pro will not work for me. My table saw is 220 volt 30 amps plug. IVac does not have a switch for this. My other tools are 220 volt 20amps and 120 volt 15 or 20 amps. I rather have ONE remote control to turn on and off the DC as needed.

What IVac (I intend to call them directly and learn more) taught me is the need for a heavy duty relay switch, or "contactor" between the DC and a remote control unit for a 110volt (or 120volt) DC running a 1 1/2 hp motor.

The Rockler/Woodcraft unit can't take the strain of a true 1 1/2 hp DC by itself.

Very surprised there were no other similiar complaints on this site or Rockler not alerting the manufacturer of a problem. I, for one, returned one unit for a refund to them.

It was the IVac info which appears to solve the problem.

If I learn anything new, I'll let ou know.

[Dan Hintz]

I went with the heavy-duty 240V, 20A relays from X-10... runs my 2HP DC just fine.

[ian maybury]

Good to hear that your dust collector is not doing anything odd anyway Bob - that at least sidelines some negative possibilities.

I'm no expert and not familiar with those iVac units. But unless i've got the wrong end of the stick something seems a little odd. As in so far as I know plugs, wiring and sockets normally have more than enough current carrying capacity to handle short term start up surges. i.e. when you select sockets you normally match its rated amps to the maximum steady state amps of the load the circuit is designed for - there's no need to add any cushion.

There are exceptions to that rule, but not many. e.g. sizing circuit breakers - but that's because they by design pop very quickly if the rated current is exceeded. Sockets on the other hand normally have a cushion by design that means they can easily dissipate the heat effects of a momentary overload like this - plus handle variations in amps arising from variations in the supply voltage as discussed here.

That's not to say that you couldn't by repeatedly switching the device on and off so that it doesn't have time to dissipate the heat from earlier starts cause a problem - but in that case it's likely the dust system motor or maybe the breaker would quit too so it's not a good operating plan. i.e. it's often better to let things run.

Another thought. Some of those units switch the dust system plus another device such as a saw or whatever. Is it somehow possible that the amps the unit is rated for is the total load of both the dust system and the device being switched, and that the combination adds up to more than what it's rated for?

If in fact the unit checks out as handling amps less (even slightly) than what it's rated for then it should be OK. If it's failing it points to some sort of a problem in the socket. Sockets do on occasion suffer from overheating. One cause at least can be a bent blade that doesn't contact the plug pin over a large enough area.

You could in effect use the device to switch a relay on a higher rated (higher amp) circuit if the current is in fact higher than what it's rated for, but again if it's failing at amps below those it's designed and marked for it points to a fault in the unit and i'd want to get to the bottom of that first....

ian

[Van Huskey]

Joe, just read your newest response. Finally got a amp meter and tested my Delta 1 1/2 hp dust collector. While it was in spec., you're right about cycling on and off putting a strain on the system; including the remote control unit. My DC started up pulling 67amps!, then quickly settled down to 14.1 to 14.7 amps on a steady run. However, I just don't like the noise running it while it is not being used so I do cycle.

.

I bet the actual inrush was more like 150 amps for 20ms or so and bet the peak was well over 200 amps, just WAY too fast for anything short of a recorder to register.

[Bob Landel]

Ian, thanks for your help, but I hope it is settled. The inexpensive remotes offered over here by Rockler/Woodcraft and others are made in Taiwan. The sockets may be suspect even if rated for 15amps. In addition, I plug it into a 20amp cuicuit, not that should be a problem in itself.

I believe the problem is the startup amp surge of my DC and my constantly cycling.

The solution is to install a contactor between the DC and the remote.

The IVac people clearly state this on their site.

[Curt Harms]

Being occasionally the curmudgeon, I'd be tempted to not do a remote at all. A contactor with a 28 volt coil and a few start/stop stations connected with inexpensive wire (remember it's low voltage pretty low amperage, maybe 18 ga. speaker wire might work) and there's no concern about turning on when it shouldn't, not turning on when it should etc. etc.

[Matthew Sherman]

It's my understanding that all outlets are 120 volt or 240 volt and that 110 is just a laypersons number. You are definitely safe using a 120v 20 amp.

Yes, that is correct. The amperage is the more important number concerning proper sizing of the outlet and wire. However if you measure your house voltage it should be right around 120v now days. Even at far runs (which really aren't that far in a typical house) it shouldn't be far off. Service voltage at your box should be within 114-126. If it is out of this range for any length of time other then a short spike you should contact your electric company.

Quick story... we had a UPS backup system reporting high voltages at one of sites and causing outages. Usually hovering around 126-127. After keeping on the electric company about the voltage issue they sent a crew to check and found a bad transformer.