LumberJocks

Basic Electrical Question (240v TS + DC)

  • Advertise with us

« back to Power Tools, Hardware and Accessories forum

Forum topic by cochranjd posted 11-15-2017 05:34 PM 337 views 0 times favorited 12 replies Add to Favorites Watch
View cochranjd's profile

cochranjd

10 posts in 298 days


11-15-2017 05:34 PM

Hey all – quick question that I think I’m clear on, but wanted to make sure.

About a year ago, I started really diving into woodworking and one of my purchases was a nice (for me) table saw. I got a Grizzly G0715p which I ultimately left at 240v and added a 240v receptical.

It’s a single receptical with 12-2 wire and a 20-amp double pole breaker.

All was well as my only 240v tools are still my table saw and my band saw, which are never in use at the same time.

I’ve had a JET dust collector fall in my lap, so I’m replacing my harbor freight model, but I now need to run 2 240v tools simultaneously (based on my research, both my TS + DC & BS + DC draws should be sufficiently low to use the same circuit).

My question is can I simply swap out the receptical for something like this:

https://www.amazon.com/Leviton-5822-W-Receptacle-Commercial-Grounding/dp/B000U3I1S0/ref=sr_1_3?ie=UTF8&qid=1447762799&sr=8-3&keywords=20A%2F240V+duplex

and go on about my business or is there anything else to consider?

I don’t have any room left on the main panel (where the current 240v double pole breaker is) but I do have a 60 amp subpanel right next to it that has room. I haven’t dug in to see what all is connected to the subpanel, but my initial thoughts are that I can probably run another circuit there if absolutely necessary.

I plan to get a 3HP next spring at which point I’m guessing I’ll have to go with another circuit, but I’m trying to put that off until then if possible.

Thoughts?


12 replies so far

View toolie's profile

toolie

2094 posts in 2462 days


#1 posted 11-15-2017 06:25 PM

it will work. whether its code compliant is another issue. i run my 240 rikon 10-340 and Delta 50-850 on the same 20A circuit without incident. my subpanel is 30A.

-- there's a solution to every problem.......you just have to be willing to find it.

View jonah's profile

jonah

1443 posts in 3132 days


#2 posted 11-15-2017 06:37 PM

I believe it’s kosher per the NEC to run multiple 20A receptacles on one circuit. I know for a fact you can’t do that with anything bigger than 20A.

If the subpanel is close and accessible, you’d honestly be better off playing it safe and running another 12/2 wire to the new receptacle, rather than hanging a new one off the existing one.

View Fred Hargis's profile

Fred Hargis

4756 posts in 2327 days


#3 posted 11-15-2017 06:55 PM

I have a couple of those in my shop and they will work just fine.

-- Our village hasn't lost it's idiot, he was elected to congress.

View cochranjd's profile

cochranjd

10 posts in 298 days


#4 posted 11-15-2017 07:15 PM

Thanks guys -

I double checked last night and my subpanl has capacity for another circuit (double pole) and as I’m running the HF on that subpanel right now and it doesn’t trip, it should have plenty of capacity for the new circiut as well (since I will no longer be running the HF). My plan is to get the duplex receptical for now and then at some point over the next few months run the new circuit.

View William Shelley's profile

William Shelley

477 posts in 1303 days


#5 posted 11-15-2017 07:21 PM

NEC rules for receptacles are pretty bunk when applied to a shop. I believe that under residential NEC rules, no 240V circuit is allowed to serve more than one utilization equipment device. I think that’s to prevent someone from using the same circuit to run a dryer and a heater, for example.

-- Woodworking from an engineer's perspective

View cochranjd's profile

cochranjd

10 posts in 298 days


#6 posted 11-15-2017 07:26 PM

I thought I had read that with regards to 30 amp circuits, but that 20 amp circuits were fine.

Either way, I suppose I can always wire in the duplex, then when I do run the second circuit, I can wire the single back in place.

View crank49's profile

crank49

4026 posts in 2805 days


#7 posted 11-15-2017 08:54 PM

CAUTION! That receptacle you linked to is a 20A 120V receptacle. Any 120V device with a standard 120V plug will plug into it without a hitch. Till you turn it on! That’s when the sparks start to fly. The 250V rating on the description means only that it’s capable of a maximum of 250V without breaking down. Most 120V components are rated like this. Gear for 480V is always rated for 600V. Same thing. If you want to connect multiple 240V tools to one circuit, OK, but the receptacles need to be a design that 120V tools cannot be plugged into.

View cochranjd's profile

cochranjd

10 posts in 298 days


#8 posted 11-15-2017 09:11 PM

crank – are we looking at the same thing?

The one I’m looking at has 2 horizontal slits, one which also a vertical slit.

120v devices require 2 vertical slits.

Am I misunderstanding something?

View William Shelley's profile

William Shelley

477 posts in 1303 days


#9 posted 11-15-2017 09:37 PM



crank – are we looking at the same thing?

The one I m looking at has 2 horizontal slits, one which also a vertical slit.

120v devices require 2 vertical slits.

Am I misunderstanding something?

- cochranjd

Nope, you have the correct receptacle.

-- Woodworking from an engineer's perspective

View MrUnix's profile

MrUnix

5979 posts in 2033 days


#10 posted 11-15-2017 09:42 PM

CAUTION! That receptacle you linked to is a 20A 120V receptacle.
- crank49
crank – are we looking at the same thing?
- cochranjd

It’s a NEMA 6-20, which is rated for 240V. Here are the NEMA plug configurations:

Cheers,
Brad

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

View William Shelley's profile

William Shelley

477 posts in 1303 days


#11 posted 11-15-2017 10:11 PM

Personally, I prefer the twist-lock receptacles over straight-blade types. But, both the receptacle and the cord plug end are more expensive.

-- Woodworking from an engineer's perspective

View sawdustdad's profile

sawdustdad

334 posts in 719 days


#12 posted 11-16-2017 02:29 AM

OP, should be no problem doing what you want to do. I do like separate circuits for each machine, but it’s not necessary. When I wired my shop two years ago, I installed 7 separate 240V tool circuits—Planer, Dust collector, Table saw, Air compressor, welder, shaper, spare. I was unsure of exact location of TS, shaper and the planer, so two of the 30A circuits had two different outlets each, about 10 feet apart, The electrical inspector had no issues. I used twist lock receptacles. I created twist lock to standard 240V plug pigtails for several machines. Others, I just changed the plug to twist lock. If not familiar with such stuff, be sure to get a pro to help you. When I upgrade to a larger jointer, I’ll likely have to share one of the circuits. The spare is not in the right location…

-- Murphy's Carpentry Corollary #3: Half of all boards cut to a specific length will be too short.

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com