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stupid question - voltage..

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Forum topic by jerkylips posted 10-02-2018 07:10 PM 602 views 0 times favorited 16 replies Add to Favorites Watch
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jerkylips

495 posts in 2987 days


10-02-2018 07:10 PM

When looking at the voltage on a saw/motor, you often see 110/120, as if they are interchangeable.

I’ve noticed recently that some brands of cabinet saws are listed as 240v, 230v or 220v. Is there any difference, in terms of wiring requirements? I understand the difference between single phase and 3 phase, but I’m talking strictly single phase.

I have a separate panel in the garage, but nothing wired yet – just wondering if it’s something I need to think about before buying or wiring..


16 replies so far

View MrUnix's profile

MrUnix

7404 posts in 2615 days


#1 posted 10-02-2018 07:53 PM

Is there any difference, in terms of wiring requirements?

No – they are all referring to the same voltage range.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View smitdog's profile

smitdog

433 posts in 2522 days


#2 posted 10-02-2018 07:56 PM

To my understanding – and I’m far from an expert – is that depending on where you live the incoming line voltage can range between 220 and 240 (roughly). For most machines with a simple motor it means almost nothing, maybe a slight variance in HP output of the motor. For some sensitive electronic equipment the variance in voltage can be a problem. In my print shop I have a large production level digital printer that has to be plugged into a voltage converter that steps down our incoming 240 down to 220 for the machine. Apparently it can’t handle 240 V so it needs what’s called a “Power Conditioner” to operate at the correct voltage.

But for something like shop equipment you won’t see any real-world difference at all.

-- Jarrett - Mount Vernon, Ohio

View jerkylips's profile

jerkylips

495 posts in 2987 days


#3 posted 10-02-2018 08:28 PM

Thanks much, everyone! That’s kind of what I thought, but wasn’t really sure.

View CaptainKlutz's profile

CaptainKlutz

1490 posts in 1911 days


#4 posted 10-02-2018 08:31 PM

For US household wiring, there is no difference. You get voltage from power company they want to give you. :) Most modern homes are supplied either 220VAC or 240VAC single phase. This translates into 110/120 for power from a single leg referenced to neutral.
US based household devices are usually rated for 208-240V or 105-125V AC and present no issues with standard household wiring. Typically only time need to worry about motor voltage rating is when you find motors rated for a single voltage that is more than +/- 5% from your supply voltage.

——————————-
Longer answer, just in case:

The reason for various voltage ratings is due to how power companies reduce the voltage down from transportation voltages (10KV+ 3PH) using various delta and wye transformer configurations. Voltage ratings also have tolerance to allow normal fluctuations due voltage drop under heavily loaded conditions. Power line voltage reduction gets complicated quickly, search wiki if you want to learn more.

In industrial wiring (and some old homes); you can find less common 208VAC supply voltage. A 208V supply line can present some unique challenges for large HP industrial motors. There are ‘universal’ replacement motors with voltage taps to allow for differences between 208-240V, but many older motors found on antique woodworking equipment may not. Another consideration is magnetic motor starter required on motors larger than 1.5-2.0HP per code. Motor starter has overload protection circuitry inside that also needs to be modified depending on voltage supplied (usually wire to different tap, but check rating on your box). Running a motor on voltage lower than name plate rating is not recommended as it will cause; power loss, overheating, and premature failure. So depending on equipment being used with 208VAC power, you may have to either; replace 220/240 motor/starter, rewire motor/starter voltage taps, or install a local 208:240V transformer.
IMHO – If you find that you have less common 208V household supply and since needed to ask in this forum about panel voltage differences; you likely should be contacting a licensed electrician to wire your new panel and review your equipment installation. A qualified professional can ensure that you stay safe.

Best Luck.

-- I'm an engineer not a woodworker, but I can randomly find useful tools and furniture inside a pile of lumber!

View ArtMann's profile

ArtMann

1396 posts in 1233 days


#5 posted 10-02-2018 09:14 PM

120VAC and 240VAC are nominal throughout the entire USA. The tolerance permitted varies from location to location but if the voltage in your house reads 110/220 VAC all the time then you have a borderline problem. The terminology is an erroneous holdover from decades ago.

View MrRon's profile

MrRon

5564 posts in 3660 days


#6 posted 10-02-2018 09:41 PM

The voltage we get from the utility company vluctuates during the day because of periods of high usage and non peak hours. It apparently amounts to ± 5 volts.

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MrRon

5564 posts in 3660 days


#7 posted 10-02-2018 09:43 PM

The voltage we get from the utility company vluctuates during the day because of periods of high usage and non peak hours. It apparently amounts to ± 5 volts.

View BroncoBrian's profile

BroncoBrian

875 posts in 2375 days


#8 posted 10-02-2018 09:53 PM



For US household wiring, there is no difference. You get voltage from power company they want to give you. :) Most modern homes are supplied either 220VAC or 240VAC single phase. This translates into 110/120 for power from a single leg referenced to neutral.
US based household devices are usually rated for 208-240V or 105-125V AC and present no issues with standard household wiring. Typically only time need to worry about motor voltage rating is when you find motors rated for a single voltage that is more than +/- 5% from your supply voltage.

- CaptainKlutz

Good answer. If you are in north Colorado Springs, you get 119 volts about 95% of the time. I’ve installed a lot of electronics in homes and rarely see anything outside of 115 – 121 volts.

-- A severed foot is the ultimate stocking stuffer.

View BlasterStumps's profile

BlasterStumps

1323 posts in 856 days


#9 posted 10-02-2018 10:03 PM

If you are still in the planning stage with that panel you mentioned, then I would suggest putting in at least one dedicated 240 Volt circuit along with your requirements for 120 Volt GFCI circuits.

-- "I build for function first, looks second. Most times I never get around to looks." - Mike, western Colorado

View CaptainKlutz's profile

CaptainKlutz

1490 posts in 1911 days


#10 posted 10-02-2018 11:37 PM

If you feel need to understand differences between various supply voltages found in US power system, might want to read a thread on an electrician’s forum that wanted to know best way to answer the OP question:

https://www.electriciantalk.com/f2/208-220-240-a-13116/

Hehe, it is not simple… :)

-- I'm an engineer not a woodworker, but I can randomly find useful tools and furniture inside a pile of lumber!

View lumbering_on's profile

lumbering_on

578 posts in 906 days


#11 posted 10-02-2018 11:43 PM



For US household wiring, there is no difference. You get voltage from power company they want to give you. :) Most modern homes are supplied either 220VAC or 240VAC single phase. This translates into 110/120 for power from a single leg referenced to neutral.
US based household devices are usually rated for 208-240V or 105-125V AC and present no issues with standard household wiring. Typically only time need to worry about motor voltage rating is when you find motors rated for a single voltage that is more than +/- 5% from your supply voltage.

——————————-
Longer answer, just in case:

The reason for various voltage ratings is due to how power companies reduce the voltage down from transportation voltages (10KV+ 3PH) using various delta and wye transformer configurations. Voltage ratings also have tolerance to allow normal fluctuations due voltage drop under heavily loaded conditions. Power line voltage reduction gets complicated quickly, search wiki if you want to learn more.

In industrial wiring (and some old homes); you can find less common 208VAC supply voltage. A 208V supply line can present some unique challenges for large HP industrial motors. There are universal replacement motors with voltage taps to allow for differences between 208-240V, but many older motors found on antique woodworking equipment may not. Another consideration is magnetic motor starter required on motors larger than 1.5-2.0HP per code. Motor starter has overload protection circuitry inside that also needs to be modified depending on voltage supplied (usually wire to different tap, but check rating on your box). Running a motor on voltage lower than name plate rating is not recommended as it will cause; power loss, overheating, and premature failure. So depending on equipment being used with 208VAC power, you may have to either; replace 220/240 motor/starter, rewire motor/starter voltage taps, or install a local 208:240V transformer.
IMHO – If you find that you have less common 208V household supply and since needed to ask in this forum about panel voltage differences; you likely should be contacting a licensed electrician to wire your new panel and review your equipment installation. A qualified professional can ensure that you stay safe.

Best Luck.

- CaptainKlutz

Thanks for bringing back nightmares of the Wye line-to Neutral and Wye line-to-line just when I was over it. :(

View Madmark2's profile

Madmark2

472 posts in 1005 days


#12 posted 10-03-2018 04:32 AM

220v is derived as a single phase voltage directly from a local single phase transformer. 208v is derived from a three phase source from two legs of the 3 phase source. Many equipment are sporting universal power supplies that will work from 85v to 250v, sadly electric motors aren’t as flexible.

M

View teejk02's profile

teejk02

501 posts in 1542 days


#13 posted 10-03-2018 02:22 PM

Years ago some companies split the difference and list stuff as 115v. Around here my voltage reads 121v but I’ve lived in places where it was closer to 110v.

View jerkylips's profile

jerkylips

495 posts in 2987 days


#14 posted 10-03-2018 02:37 PM



If you are still in the planning stage with that panel you mentioned, then I would suggest putting in at least one dedicated 240 Volt circuit along with your requirements for 120 Volt GFCI circuits.

- BlasterStumps


We just moved into the house, but the garage walls are still open (not insulated/drywalled yet) because i wasn’t sure where I wanted my stuff set up. I have an electrician friend that said as long as the walls are open, he can easily run some extra lines from the panel.

View TheFridge's profile

TheFridge

10858 posts in 1903 days


#15 posted 10-03-2018 03:20 PM

No.

I’ve wired 208 to labeled 220-240 motors with no issues.

-- Shooting down the walls of heartache. Bang bang. I am. The warrior.

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