Wiring question 240v to my jointer

[gygeneral]

In my garage I have a 30 amp 220v breaker in my subpanel, wired with #10 wire, going to 3 -30 amp welder type receptacles.

I just bought a jointer motor 220v, 15 amp motor with a smaller 220v plug on the end. I believe its a 6-20 plug


I would like to simply change out one of the three existing receptacles with the appropriate smaller 220v to match the plug on the jointer.

Is this something I can do? or do I have to either swap out the 30 amp breakers to 20 amp , then the existing receptacles I would have to remove so I don't accidentally plug a tool with a higher than 20 amp load. I don't think the no 10 wire will be an issue.

Thanks

 

[carlaisle]

Change the plug on the jointer to match the available receptacles.

 

[gygeneral]

Change the plug on the jointer to match the available receptacles.

I guess I'm asking if this can cause a situation where the motor for some reason draws more amps due to a malfunction and causes a fire.

 

[mike93lx]

I guess I'm asking if this can cause a situation where the motor for some reason draws more amps due to a malfunction and causes a fire.

A fire isn't going to start from it pulling an extra few amps.

I'd likely change the jointer plug as well

 

[Firebrick43]

If you have 6-30r receptacles they are only HP rated to 2 hp.

15 FLA at 240v is almost 3 hp.

Doe your new motor have an overload built in or the machine it’s installed in per 430.32?

 

[gygeneral]

If you have 6-30r receptacles they are only HP rated to 2 hp.

15 FLA at 240v is almost 3 hp.

Doe your new motor have an overload built in or the machine it’s installed in per 430.32?

I read the manual , no mention of overload protection, all it says it must be on a circuit 240 with minimum 20amp.

 

[gygeneral]

Found the wiring diagram, I see Thermal Overload there in the mag switch, I'm not an electrian but is this what i think it is.

 

[theoldwizard1]

In my garage I have a 30 amp 220v breaker in my subpanel, wired with #10 wire, going to 3 -30 amp welder type receptacles.

I always thought you were only allowed ONE receptacle on a 240V circuit ?

 

[Firebrick43]

Found the wiring diagram, I see Thermal Overload there in the mag switch, I'm not an electrian but is this what i think it is.

That is it and therefore your good.

Many are built into the motor itself and people will not be aware of that when they replace it which is why I asked.

 

[gygeneral]

That is it and therefore your good.

Many are built into the motor itself and people will not be aware of that when they replace it which is why I asked.

Thanks for confirming, so to recap , I can either change the plug on the jointer to a 6-30p or change out one of the 6-30r receptacles to the one that matches the plug on my jointer which is a 6-20p. I guess there are also adapters I can get, altough more expensive, it would allow me to plug my jointer in any of the 3 plugs I already have.

 

[Firebrick43]

Your manual says no adapters and at that horsepower I would agree. Most of the adapters are not UL listed anyways, only a few lower amp ones are.

I would switch out the plug to 6-30p

 

[mikedodge]

I'd rather change the plug on the one machine then one outlet. Then someone comes along in the future and thinks that outlet is protected at the lower amperage, or you can't plug something else there if it's the more convenient location.

 

[Norcal]

I always thought you were only allowed ONE receptacle on a 240V circuit ?

Per the IRC, yes, the NEC, has no such language.

 

[Firebrick43]

I always thought you were only allowed ONE receptacle on a 240V circuit ?

210.23(C)allows multiple receptacles for “Equipment Not Fastened in Place” as long as you don’t exceed 80% of the rating of the wire/circuit breaker.

15 amps on a 30 amp circuit is well within the confines of the NEC.

 

[gygeneral]

Many thanks for the advice, Changing out the plug makes most sense and it accomplishes leaving my receptacles alone and then I can plug my jointer in any of the three receptacles.

 

[The Cobbler]

if there's warranty on the jointer, I would not change out the plug . just saying

 

[gygeneral]

if there's warranty on the jointer, I would not change out the plug . just saying

This is a 10 year old jointer, so no warranty, I noticed in the manual it said it did not come with a plug and the previous owner said he put a plug on it to match his shop

 

[mm08822]

6-30p is good enough. Don't open under load. Starter has o/l protection.

Maybe 6-30P's are your go to as you get more equipment......no adapters, multiple locations to plug in.

If you ever need an extension cord....6-30's on both ends are the answer. It's a home shop and you are there when equipment is running.

 

[micromind]

I guess I'm asking if this can cause a situation where the motor for some reason draws more amps due to a malfunction and causes a fire.

With motors, the circuit breaker is there for short-circuit and ground-fault protection, the overload will protect the motor and wire.

The largest breaker allowed for a 3HP single-phase motor operating at 230 volts is 45 amps. There is no minimum.

 

[gygeneral]

Can someone explain to me why some 3hp motors have an amp rating of 15 amps and I've seen some as low as 9 amp. I noticed when I was shopping for a new jointer, eventually buying this used one. Just curious, is there some kind of efficiency factors involved here, like a good motor uses less amps as opposed to a crappy motor.

 

[mike93lx]

Can someone explain to me why some 3hp motors have an amp rating of 15 amps and I've seen some as low as 9 amp. I noticed when I was shopping for a new jointer, eventually buying this used one. Just curious, is there some kind of efficiency factors involved here, like a good motor uses less amps as opposed to a crappy motor.

The ones saying 9a are lying about the HP

Many motors use the ********® scale of rating

 

[u2slow]

Can someone explain to me why some 3hp motors have an amp rating of 15 amps and I've seen some as low as 9 amp. I noticed when I was shopping for a new jointer, eventually buying this used one. Just curious, is there some kind of efficiency factors involved here, like a good motor uses less amps as opposed to a crappy motor.

It's the HP # that is fiction on lots of shop tools. Amps is amps. Capacitors may be employed, and that can reduce the running amps a little.

Efficiency difference is almost nothing these days.

 

[Stuart in MN]

Kind of like the power ratings of car stereos or home vacuum cleaners, the manufacturers pretty much make up the stuff in their ad copy.

 

[gygeneral]

Interesting, I guess like everything else these days

 

[jar944]

Just change the plug on the jointer. I have all my shop equipment on 6-50 plugs.

 

[Firebrick43]

Interesting, I guess like everything else these days

They have charts that assign Horsepower by the Full Load Amps (FLA) listed on the data plate. Just make sure you are looking at a single phase section or table and not a 3 phase table

 

[jar944]

FLA = (hp * 746) / (1.73 * V * pf * efficiency)

Pf and efficiency will be the variable between different motors.

 

[micromind]

They have charts that assign Horsepower by the Full Load Amps (FLA) listed on the data plate. Just make sure you are looking at a single phase section or table and not a 3 phase table

Typical online chart........partly accurate, partly way off.........

Note how it states that 'IN ALL CASES the current shown on the motor nameplate is the correct value for that particular motor and takes precedence over any value shown in this table'.

NEC 430.6(A)(1) states that the table values shall be used to determine the ampacity of conductors or amp rating of switches, short-circuit and ground-fault protection instead of the actual current rating marked on the motor nameplate.

Which one would you use? The code or some idiotic internet chart?

P.S. The values listed in the chart are the same as listed in the code.

 

[Firebrick43]

Typical online chart........partly accurate, partly way off.........

Note how it states that 'IN ALL CASES the current shown on the motor nameplate is the correct value for that particular motor and takes precedence over any value shown in this table'.

Its a general chart. All its stating that the current(FLA) might not match up exactly with the chart due to efficiency and power factor.

Some motors are made with higher (or lower) quality materials and methods giving them higher (or lower) efficiency. There is no way for all of them to match up exactly with a chart.

The chart is simply to corollate FLA to HP , and the chart works well for that. The OP saw some at 15 amps which is a little under the 17 amps on the chart for 3 hp but not too far off. We have no idea if its an efficiency thing or its really a 2.5 hp motor without more info.

But we can see that the 9 amp motor by the chart is in no way close to 3 hp, its half of that. Unless some new tech has been invented that none of know about, there is no possible way its a 3 hp motor

There was no implied notion to use the chart to size conductors and other current sized components?

 

[mm08822]

They have charts that assign Horsepower by the Full Load Amps (FLA) listed on the data plate. Just make sure you are looking at a single phase section or table and not a 3 phase table

Typical online chart........partly accurate, partly way off.........

Note how it states that 'IN ALL CASES the current shown on the motor nameplate is the correct value for that particular motor and takes precedence over any value shown in this table'.

NEC 430.6(A)(1) states that the table values shall be used to determine the ampacity of conductors or amp rating of switches, short-circuit and ground-fault protection instead of the actual current rating marked on the motor nameplate.

Which one would you use? The code or some idiotic internet chart?

P.S. The values listed in the chart are the same as listed in the code.

Why read the small print? Whose got time for that?? It's more useful to take things out of context.

 

[u2slow]

Typical online chart........partly accurate, partly way off.........

Note how it states that 'IN ALL CASES the current shown on the motor nameplate is the correct value for that particular motor and takes precedence over any value shown in this table'.

NEC 430.6(A)(1) states that the table values shall be used to determine the ampacity of conductors or amp rating of switches, short-circuit and ground-fault protection instead of the actual current rating marked on the motor nameplate.

Which one would you use? The code or some idiotic internet chart?

FWIW, using nameplate values is Code in Canada. Table values are for when motor/equipment is not available.

 

[gygeneral]

Just change the plug on the jointer. I have all my shop equipment on 6-50 plugs.

Today I changed out the jointer plug with a 6-30 plug. I had some issues to tighen up the terminals I'm guessing because the wire from the machine is 12/3 and this 6-30 plug is made for 10/3 I could not get them tight enough. I had to bend the terminal a little to make the opening a little smaller then I was ok. Here where I live I could only find those combo plugs that can do 30 or 50 amps, I don't if there is such a thing as a 6-30 made for 12/3. Anyhow seems to work and everything was nice and tight

 

[wyliesdiesels]

They have charts that assign Horsepower by the Full Load Amps (FLA) listed on the data plate. Just make sure you are looking at a single phase section or table and not a 3 phase table

thats a full load current chart and it doesnt correspond to FLAs on nameplates as the values in these charts are much higher. also the codes have been updated to 430.248 & .250.

 

[Bert_]

Today I changed out the jointer plug with a 6-30 plug. I had some issues to tighen up the terminals I'm guessing because the wire from the machine is 12/3 and this 6-30 plug is made for 10/3 I could not get them tight enough. I had to bend the terminal a little to make the opening a little smaller then I was ok. Here where I live I could only find those combo plugs that can do 30 or 50 amps, I don't if there is such a thing as a 6-30 made for 12/3. Anyhow seems to work and everything was nice and tight

For smaller wire I will strip extra and fold the wire. Ends up 2x as thick.

 

[Firebrick43]

thats a full load current chart and it doesnt correspond to FLAs on nameplates as the values in these charts are much higher. also the codes have been updated to 430.248 & .250.

Did you read the context on what I was replying to that the OP asked? Did you read post 29? It was in reference to a motor that claimed it was 3hp but only pulled 9 amps.

I wasn't suggested to size anything based off the chart.

You can read the chart but not the rest of the thread? And the values for 240v single phase motors on 430.248 are the same from the version I posted?

 

[gygeneral]

For smaller wire I will strip extra and fold the wire. Ends up 2x as thick.

Now why didn't I think of that, a lot easier than what I did, I'll know next time, thanks

 

[wyliesdiesels]

Did you read the context on what I was replying to that the OP asked? Did you read post 29? It was in reference to a motor that claimed it was 3hp but only pulled 9 amps.

I wasn't suggested to size anything based off the chart.

You can read the chart but not the rest of the thread? And the values for 240v single phase motors on 430.248 are the same from the version I posted?

youre not really paying attention here

what i was alluding to is that FLA and FLC are not one in the same.

you claimed there are charts that assign HP based on FLA and that chart you posted claimed to be typical FLA ratings but clearly its an FLC chart from the NEC, which are NOT typical FLA ratings at all. The FLC ratings are MAX amp ratings for a motor of a given HP. so the chart is misleading and what you claimed is misleading as well.

You cant use an FLA rating off a motor nameplate and then use an FLC chart from the NEC to guess the HP rating. you will get it wrong because FLAs and FLCs from the NEC table do not coincide. you are to use the amp rating in the FLC chart based on the HP rating from the motor nameplate.

The reason i brought up 430.248 and .250 is because at the bottom of the chart it claims the data was from 430-148 and 430-150 which is really old.