Will my new drum sander work in my shop (electrical ?)

[Dan Ness]

So I just got a 24" Drum Sander, and the plug on it is a L6-30 NEMA (twist lock plug). My wall outlet is a standard 6-20 receptacle. I have seen online that you can get an adapter which would allow me to plug the L6-30 into my 6-20 wall outlet, but the question is will it run without tripping breakers or burning down my shop?

The instruction say I need at least 27 amps for the drum sander, and when I look at my breaker box in the shop it looks like 2 x 20amp breakers connected together, and the bar that turns them on and off is labeled 30. So I am assuming that means it is a 30 amp breaker and that it will work. . .right??

[Mark Bolton]

Im not sure what you mean when you say "it looks like 2 x 20amp breakers connected together, and the bar that turns them on and off is labeled 30". Do they say 20 on them anywhere or are you just saying they look like a single pole breaker connected together? Thats what a double pole breaker is. So if your breaker looks like this:

http://media.toolking.com/catalog/pr...it_Breaker.jpg

then yes, you will be fine.

With regards to the plug your options would be:

- change the receptacle in your garage to match the plug.

- cut/remove the plug from the machine an install a plug matching your receptacle.

- do away with the plug all together and hard wire the machine

[Dan Ness]

Yup, that is exactly what my breaker looks like. Instead of changing receptacles, or cutting up the plug, I was planning on buying an adapter, which I have seen online that basically has the L6-30 female on one end and the 6-20 male on the other end, and is about 12 inches long. Therefore I could plug the machine into the adapter, and the adapter into the wall. Does that sound about right?

(and yes, as you can tell I am a novice when it comes to electrical and can't be trusted to do much more than just plug / unplug machines)

[David Kumm]

If the breakers say 30 amps and the wiring is 10 gauge the only question is whether the 20 amp plug and receptacle can stand the additional amperage. I would not chance it and replace the receptacle. I can understand a adapter going from 30 to 20 but not the other way around. Dave

[Dan Ness]

David. . .so you are saying that if I get the adapter, I might have something go wrong in the actual wall receptacle because it is only rated at 20, even though the wiring and the breaker will be fine. So I would have to change the actual receptacle to be safe? Is it normal then for a 20 amp receptacle to be wired to a 30 amp breaker? Shouldn't the breaker match the receptacle?

[Mark Bolton]

Good catch David. I didnt catch the 6-20 just had the twist lock in mind. Hopefully not 12 gauge wiring.

[David Kumm]

Yes, I'd change the receptacle. If the motor on the machine originally installed only needed a 20 amp plug it was fine. The breaker is to protect the wiring. Just be sure the wiring in the box is #10 when you change the receptacle. Dave

[Jim Neeley]

Dan,

With a sander whose instructions indicate you need 27A, you should not use a L6-30R (R=receptacle) to 6-20P (P=plug) adapter. There are requirements to utilize them.

I once installed a 1500W inverter / 50A battery charger that provided pass-through power in my boat. The shore power cable had an L6-30P connector, however they provided a L6-30R to 6-20P adapter, just like you're proposing with the kit. The instructions were VERY clear that the adapter was only to be used when 30A service was not available and, when using it you were to toggle a switch that limited the draw of the inverter to less than 16A total electronically, within the inverter. This was provided to permit people to charge up their boat when at home (where 30A power likely isn't available), with the understanding that if they drew a lot of power they'd be drawing down the batteries. A lot better than nothing for them.

Your sander has no such limiter and you should not use a 6-20R if they are telling you that the sander draws more than 16A for other than initial startup. High current + time on a small receptacle = heat buildup. :-)

Jim

[Steve Milito]

Adapters can be dangerous. Just because you know the intended use of the adapter does not mean that someone else might not use the adaptor in a manner that you didn't intend.
I would replace the receptacle assuming you have 10 gauge wire running to the breaker.

[Jim Neeley]

+1 on replacing the receptacle.

[Dan Ness]

So what you are all saying is that my idea for an adapter is perfect, and I should run with it. . .j/k I guess it is time to call the electrician and add a 30amp receptacle to my shop.

Thanks for all the input!

[Steve Meliza]

The 6-20 receptacle on a 30A circuit is a violation of the National Electrical Code because putting >20A through it could result in a visit by your local fire department for a BBQ. You need to verify that the wiring is #10 and replace the outlet with one rated for 30A. It's really easy to do yourself so take a look at it before you call the electrician. As long as you connect the ground wire to the correct terminal then you're good to go as the other two wires can connect to either of the "hot" terminals of the outlet.

You need an L6-30R outlet like this:
http://www.homedepot.com/p/Pass-Seym...6#.UYkk34LwEeM

You might need a different outlet cover so either take your old one with you to compare it or just plan to buy a new one when you get the new outlet. On the old 6-20 outlet ground is the center pin and looks just like the ground pin on a normal 120V outlet. On the L6-30R outlet the ground pin looks like a large "L" so just move that wire (green or bare copper wire) from one ground pin to the other (the ground terminal should be clearly marked on the new outlet) then move over the other two wires to either terminal. Make sure to shut off the breaker before you start.

[Jim Neeley]

That is a oversimplification, Steve, and is not strictly true for motor-driven circuits where the motor or motor control circuit contains built-in protection. While somewhat off-topic (i recommended installing a L6-30R) it's an important clarification for motor circuits.

Let me give you a specific example that I have thoroughly researched.

I own one of the new-style "5hp" Delta Unisaws which contains a Marathon induction motor with a nameplate rating of 20A. It was also factory-supplied with a 6-20P. The Delta owners manual recommends the installation of a 40A breaker in order to handle start-up current. I'm up, as likely are you, on the nuances of the 225% rule for sizing motor circuit breakers. In synopsis it would be kosher to install the 40A breaker on the 20A nameplate assuming that was required to handle the inrush current.

My research involved the use of the 6-20P plug on the end which would require the 40A breaker to feed a 6-20R receptacle, a 6-20R on a motor with 20A nameplate and further, 6-20R's only accept up to 10ga wire. My research worked this back through Delta's engineering, Marathon's engineering to the NFPA70 (NEC) code board itself and finally to my local AHJ (inspector), in order to verify the obvious solution (40A breaker, #10 wire, 6-20R) combination would be legitimate. This was confirmed a legitimate solution by all parties involved since Delta has gotten approval on the saw with the plug installed.

I do not *like* the solution as it is only approved if my saw is plugged into the circuit but it does meet code for that use. Therefore I have labeled that receptacle "For Table Saw Use Only" and will choose to replace that plug / receptacle with a L6-30P/L6-30R (likewise wired) when I rewire my shop (since it has 10ga), even though I'm the only one who works in the shop.

Still, strictly speaking, it is legal in some circumstances to do so. Not when the motor is labeled 27A however. :-)

Jim

[Wade Lippman]

I do not *like* the solution as it is only approved if my saw is plugged into the circuit but it does meet code for that use. Therefore I have labeled that receptacle "For Table Saw Use Only" and will choose to replace that plug / receptacle with a L6-30P/L6-30R (likewise wired) when I rewire my shop (since it has 10ga), even though I'm the only one who works in the shop.
Jim

I don't like it either, and would like to see where in code there is an exception for house wiring just because the tool manufacturer says it is okay.

Rather off topic, but my cyclone is 22a and the manufacturer recommends a 40a circuit. I am using a 30a circuit without incident; the breaker curve shows a 30a breaker will handle more than a 22a motor will throw at it.