New Jointer electrical question

[brian cammarata]

Howdy folks, I forgot to sleep at a Holiday Inn Express last night so my electrical knowledge is a bit lacking. I think this is simple issue but wanted to test waters with forum knowledge base first.

In my workshop / space, where I want this 8" jointer to go, I currently have it wired for my 5hp dual drum sander, with a a L6-30R on a 30 amp breaker in my box. My new grizzly jointer G0856 came with 6-20 plug. Can I just cut that plug off and put a new L6-30P plug on that?

Is there any detriments on powering the jointer on a bigger circuit / plug than recommended?

Thanks in advance, as I am probably over thinking this

-Brian

[Ron Selzer]

Go for it, will be fine

[Mike Cutler]

Nope, you’re good. The NEC stopped at the receptacle.
There are millions of electrical devices pulling less than the amperage the supply breaker is rated for.

[Bill Dufour]

make sure the motor is wired for. 240 volts. With that plug i assume it is.
Bill D

[Cameron Wood]

I would replace the receptacle with one that fits the jointer, and save the other one for use with the sander. Much cheaper.

[Phil Gaudio]

I would replace the receptacle with one that fits the jointer, and save the other one for use with the sander. Much cheaper.
Receptacle has to be rated for the wiring in the house, so putting a receptacle rated for 20 amps on a branch circuit rated for 30 amps would not be a good idea.

[Justin Rapp]

Receptacle has to be rated for the wiring in the house, so putting a receptacle rated for 20 amps on a branch circuit rated for 30 amps would not be a good idea.

yup I agree with this. But it's easy enough to replace the plug on the jointer to a L6-30R so either machine will work. The jointer, while only requiring a 20amp circuit will work fine on a 30 amp circuit. Same idea as running an 8 amp blender in the kitchen on a 20 amp GFI circuit.

[Greg Funk]

The breaker should be a maximum of 250% of the FLA of the motor on the circuit (NEC table 430.52). In your case if the FLA is 12 the max breaker size is 30A so you should be OK.
Change the plug on the jointer to match the receptacle.

[Cameron Wood]

yup I agree with this. But it's easy enough to replace the plug on the jointer to a L6-30R so either machine will work. The jointer, while only requiring a 20amp circuit will work fine on a 30 amp circuit. Same idea as running an 8 amp blender in the kitchen on a 20 amp GFI circuit.




Household outlets including GFCI are generally 15 amp rated devices on 20 amp circuits these days, and that blender probably has #16 or smaller power cord wires- same deal with the jointer.

[Justin Rapp]

Household outlets including GFCI are generally 15 amp rated devices on 20 amp circuits these days, and that blender probably has #16 or smaller power cord wires- same deal with the jointer.


yes correct - I worded it a bit off - 20 amp circuit with 15 amp gfci protection.

[Doug Colombo]

They sell an adapter that will cover your issue - I can post a picture of it when I get home.

[Cameron Wood]

yes correct - I worded it a bit off - 20 amp circuit with 15 amp gfci protection.


My point was that hooking up the jointer with a 20 amp receptacle on a 30 amp protected circuit is equivalent to common household 20 amp circuits using 15 amp rated receptacles.

[Bill Dufour]

A quality 240 volt machine will have onboard overloads to protect the motor.
Note that most home breakers will interrupt a maximum 10,000 amps. more then that and they can not disconnect it just arcs across the open terminals.
Saw the after effects when a 12 KV overhead line dropped onto a 120 supply line. Blew open the door of the fuse box in the attic. glass fuse and melted copper flew out some where into the junk in the attic, very lucky no fire.
Bill D

[Doug Colombo]

Here are some pics of the adapter. With this you should not have to cut off / replace any plugs.

489394 489395 489396

[glenn bradley]

It is easy enough to swap either plug or receptacle, your choice. I believe your question is directed at the circuit. Your circuit and device (read outlet) are spec'd for 30 amp service. As Mike mentioned, NEC stops at the 'device' (read outlet). The breaker protects the line and device (read outlet), not your machine. If you plug a lower capacity machine into a higher capacity outlet it simply means that the circuit protection is possibly beyond the capacity of your machine. Your machine probably has a breaker or fuse to protect the motor. In practice, and I am a careful spec follower, I would probably change the plug and use the circuit as is. I would remain conscious that I have a 20 amp machine plugged into a 30 amp circuit but unless I have a questionable power plant I would not be overly concerned. If you routinely blow breakers or suffer slow-downs or brownouts I would make things right. That is, the condition of your overall infrastructure comes into play. If it is solid my concern is minimal.

[Jim Becker]

I would replace the receptacle with one that fits the jointer, and save the other one for use with the sander. Much cheaper.

Can't do this. It's a 30 amp 240v circuit and must have 30 amp terminations. Changing the jointer to use the 30 amp plug is the technically correct thing to do since it will be using that circuit.

[ray grundhoefer]

Yes you could do that however the cord on your jointer is not rated for 30 amps. Also doing it may void the warranty on your brand new jointers motor.

[Doug Colombo]

I agree on the warranty concerns cutting off the plug. In my case, I ended up getting the adapter (that I posted earlier today) to allow me to plug in my new Harvey TS. The specs for the saw (Alpha 4hp) called for a 30 amp 220 circuit, but the plug that came on the saw is a 6-20 plug. So after running the 30amp with the correct 30 amp receptacle, I got the adapter to connect the saw. So far no issues.

[Brian Runau]

I'm a novice at this circuit wiring stuff, but if I run a 15 Amp item on a 20 Amp circuit don't I give up my circuit breaker protection? So if I overload the machine I run the risk of burning it out?

[Cameron Wood]

The circuit breaker is there to keep the wires coming from the panel from overheating and causing a fire, not to protect the load at the end.

If your 15 amp item was say a large motor, it's starting current draw might trip the 20 amp circuit breaker. The idea is to have the loads on the circuit be less than the rating (2/3? forget the exact amount), although the breakers are designed to handle short overloads, like the motor starting as above.

[Brian Runau]

The circuit breaker is there to keep the wires coming from the panel from overheating and causing a fire, not to protect the load at the end.

If your 15 amp item was say a large motor, it's starting current draw might trip the 20 amp circuit breaker. The idea is to have the loads on the circuit be less than the rating (2/3? forget the exact amount), although the breakers are designed to handle short overloads, like the motor starting as above.


thanks Cameron. brian

[Jim Becker]

Yes you could do that however the cord on your jointer is not rated for 30 amps. Also doing it may void the warranty on your brand new jointers motor.
The cord doesn't have to be rated for 30 amps...it's not going to pull more than 20 because the machine will not pull more than 20. Amps are not "forced" toward the load...the load asks for the amps it needs. There is no warranty concern here and it's common/normal to put a new plug on a cord that matches the infrastructure. The higher end tools don't even come with a plug/cord...that's left up to the buyer of the machine. But one can use an adapter if they prefer if they feel a need to keep the "as bought" pristine.

[Ronald Blue]

Here are some pics of the adapter. With this you should not have to cut off / replace any plugs.

489394 489395 489396

Where did you get this Doug? I looked for one a while back and then made my own. In this case I didn't want to cut the plug off the device (dust collector remote box) in case there was an issue with it and they might say I caused it by changing the factory plug.

[Mike Cutler]

Where did you get this Doug? I looked for one a while back and then made my own. In this case I didn't want to cut the plug off the device (dust collector remote box) in case there was an issue with it and they might say I caused it by changing the factory plug.


Just about any industrial electrical supply store will have these, as well as larger appliance stores, Mc Master Carr, etc.. Any type of store that supplies tools and equipment for construction.
If they're in a Home Depot, or Lowe's, they'll probably be near the electrical aisle, or the appliance section. I've also seen them for sale in tool rental centers that rent larger electrical generators.
They are also very easy to assemble yourself, as you found out.

[Ronald Blue]

Just about any industrial electrical supply store will have these, as well as larger appliance stores, Mc Master Carr, etc.. Any type of store that supplies tools and equipment for construction.
If they're in a Home Depot, or Lowe's, they'll probably be near the electrical aisle, or the appliance section. I've also seen them for sale in tool rental centers that rent larger electrical generators.
They are also very easy to assemble yourself, as you found out.

I looked briefly at Menards and then just grabbed a female end as I already had the twist lock male and made a short adapter myself. They had a wide variety of adapter plugs and it's possible I overlooked it.

[Bill Dufour]

Cost of a new receptacle, new plug, new breaker are much higher then just one plug. If he still wants to use his 30 amp receptacle he will need to run new wire as well.
Bill D

[Jim Becker]

Cost of a new receptacle, new plug, new breaker are much higher then just one plug. If he still wants to use his 30 amp receptacle he will need to run new wire as well.
Bill D
He can run a 20 amp 240v tool on a 30 amp 240v circuit with no problem as has been noted multiple times in the thread. This is purely a plug compatibility thing and a 20 amp tool can have a 30 amp plug or an adapter that does the same.

[Bill Dufour]

I was just reminding him that he can not install a 20 amp receptacle on a line served by a 30 amp breaker. If he switches the receptacle down to 20 amps he has to switch the breaker down to match as well.
Bill D

[Jim Becker]

I was just reminding him that he can not install a 20 amp receptacle on a line served by a 30 amp breaker. If he switches the receptacle down to 20 amps he has to switch the breaker down to match as well.
Bill D
I was reacting to what you wrote in the quoted post and responded accordingly. Thanks for clarifying what you meant.

[Doug Colombo]

Where did you get this Doug? I looked for one a while back and then made my own. In this case I didn't want to cut the plug off the device (dust collector remote box) in case there was an issue with it and they might say I caused it by changing the factory plug.

I got it on Amazon. Let me see if I can find a link.

Edit: Found link

https://www.amazon.com/Locking-T-Blade-adapter-Generator-Adapter/dp/B081Q6LJKQ/ref=sr_1_4_sspa?crid=133GZ55IEI16Q&keywords=220+volt+20+amp+to+30+amp+adapter&qid=1667944751&sprefix=220+volt+20amp+to+%2Caps%2C121&sr=8-4-spons&psc=1