Electrical Question - Is this acceptable?

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  • btalover
    Forum Newbie
    • Jan 2006
    • 13
    • Baton Rouge, La, USA.

    Electrical Question - Is this acceptable?

    My small shop (11x14 converted utility room) is currently wired so that every outlet and all the lights are controlled by one 15-amp circuit. I usually get by with running my shopvac and one power tool at once. When it's cold I run an electric oil filled radiator and if I forget to turn it off that, plus the TS and SV are enough to trip the breaker.

    I just installed a small window A/C to keep the shop usable during the summer. My budget is tight, but I want to add an additional circuit that will have to suffice until I hit the lottery and run a sub-panel to do it "right".

    The only other circuit that is close runs the garage door opener. As far as I can tell, it's the only thing on that circuit. I want to tap into that circuit and run about 30' of 12/2 yellow Romex through conduit into my shop to a wall mounted duplex outlet, with one outlet being a GFCI. This circuit would run the TS and shopvac or some other combination, leaving the lights and A/C or heater on the original circuit. I have a Bosch 4000 TS, so nothing that draws a lot of current, unless I am pushing it, which doesn't happen often. That is the biggest tool I have. So far.

    My question/concern is how safe is it to tap into the garage opener circuit by cutting the existing wire near the ceiling box and splicing in the new circuit with wire nuts in a covered metal junction box? Is it OK to do that?

    My only other choice is to run an extension cord out the door and across the garage. Not something LOML would appreciate.

    Any words of wisdom appreciated!

    -steve
  • poolhound
    Veteran Member
    • Mar 2006
    • 3195
    • Phoenix, AZ
    • BT3100

    #2
    How far are you from your main panel? If its the same or not that much further you would be better off running in a 20A circuit. Your TS alone is 15A and I would guess that the circuit for the garage opener is only 15A.

    FYI you can pick up a breaker panel and 4 20A breakers from HD for relatively little ~$50. Whichever way you go the main cost is in the cable. If you were already going to run 30ft of 12-2, 50 or even 100ft is not that much more.
    Jon

    Phoenix AZ - It's a dry heat
    ________________________________

    We all make mistakes and I should know I've made enough of them
    techzibits.com

    Comment

    • LCHIEN
      Internet Fact Checker
      • Dec 2002
      • 20920
      • Katy, TX, USA.
      • BT3000 vintage 1999

      #3
      i would say if the breaker box is not easily accessible then the line used for the garage door opener is an attractive way to simply get more power. You will not be opening the door when you use the power tools. I would do it with a metal junction box and wire nuts.
      Make sure you tie down the new wire with 12" after leaving the box and every 4 ft thereafter and within 12" of the new outlet(s).

      If the power tool e.g. TS is rated for 15Amps then you are being dicey running the shop vac on the same line.
      Really it sounds like you should have a bare minimum of three - one for AC-Heat, one for tool, and one for dust collection/shop vac, but I do understand how you can scrape by with TS and SV on one line for now... just hope you don't cut anything tough.
      Loring in Katy, TX USA
      If your only tool is a hammer, you tend to treat all problems as if they were nails.
      BT3 FAQ - https://www.sawdustzone.org/forum/di...sked-questions

      Comment

      • LarryG
        The Full Monte
        • May 2004
        • 6693
        • Off The Back
        • Powermatic PM2000, BT3100-1

        #4
        Originally posted by btalover
        My question/concern is how safe is it to tap into the garage opener circuit by cutting the existing wire near the ceiling box and splicing in the new circuit with wire nuts in a covered metal junction box? Is it OK to do that?
        Entirely safe, perfectly okay, as long as you use the same gauge wire and all connections are accessible. Loring covers the particulars nicely. You will need some slack in the existing wiring in order to put a new JB somewhere out in the middle, though -- about a foot, if possible. If you can't get that, another option (that might be easier anyway) is to run your new wire straight into the box at the garage door opener, and make your wire nut connections there.

        Jon makes a good point, however. As long as you're stringing wire, if the main panel is not terribly far away you'd be MUCH better off taking a new home run back to the panel. A 15A motor load, even by itself, should be on a 20A circuit. Assuming a reasonably short run to the panel and at least one open breaker space, this option won't cost a whole lot more but will be a lot better.
        Last edited by LarryG; 06-12-2008, 07:28 AM.
        Larry

        Comment

        • btalover
          Forum Newbie
          • Jan 2006
          • 13
          • Baton Rouge, La, USA.

          #5
          Thanks guys. Unfortunately the breaker box is full, so that option is out.

          I didn't realize my TS would pull 15 amps by itself. I actually have a gadget that measures watts/amps/volts but haven't tested the TS yet. I know the heater can draw about 11 amps at full throttle. The A/C only pulls 4-5 amps.

          LarryG you raise a good point about the slack. I may have to go directly to the garage opener JB with the new wire or replace the section of wire going into the box.

          Comment

          • pelligrini
            Veteran Member
            • Apr 2007
            • 4217
            • Fort Worth, TX
            • Craftsman 21829

            #6
            What kind of lighting do you have in the garage? Could you put the garage door opener on that circuit? If so, then you could have another dedicated circuit to the shop.
            Erik

            Comment

            • LarryG
              The Full Monte
              • May 2004
              • 6693
              • Off The Back
              • Powermatic PM2000, BT3100-1

              #7
              Originally posted by btalover
              Unfortunately the breaker box is full, so that option is out.
              Well, not necessarily. It's possible (and code-legal) to put two wires onto the same breaker. Some have lugs that will accept two wires; a pigtail-like connector can be used for those that don't. If there's a 20A circuit feeding something that won't normally be running at the same time you're running your tools, you could get a new "circuit" that way. Again, the wire gauge would have to be correct for the breaker size.
              Larry

              Comment

              • poolhound
                Veteran Member
                • Mar 2006
                • 3195
                • Phoenix, AZ
                • BT3100

                #8
                Originally posted by LarryG
                Well, not necessarily. It's possible (and code-legal) to put two wires onto the same breaker. Some have lugs that will accept two wires; a pigtail-like connector can be used for those that don't. If there's a 20A circuit feeding something that won't normally be running at the same time you're running your tools, you could get a new "circuit" that way. Again, the wire gauge would have to be correct for the breaker size.
                The other way to make space is to remove one of the existing breakers and replace with a double like the one below. Now you have a space to put in a 20A breaker.

                Jon

                Phoenix AZ - It's a dry heat
                ________________________________

                We all make mistakes and I should know I've made enough of them
                techzibits.com

                Comment

                • LCHIEN
                  Internet Fact Checker
                  • Dec 2002
                  • 20920
                  • Katy, TX, USA.
                  • BT3000 vintage 1999

                  #9
                  Originally posted by btalover
                  Thanks guys. Unfortunately the breaker box is full, so that option is out.

                  I didn't realize my TS would pull 15 amps by itself. I actually have a gadget that measures watts/amps/volts but haven't tested the TS yet. I know the heater can draw about 11 amps at full throttle. The A/C only pulls 4-5 amps.

                  LarryG you raise a good point about the slack. I may have to go directly to the garage opener JB with the new wire or replace the section of wire going into the box.
                  Look at the rating plate on the TS. Its likely to be close to 15A.
                  oN HEATERS AND Vacs and dust collectors and fans, they are likely to draw what the nampelate says when they run.
                  ON TS and power tools, they'll draw close to what the nameplate says when they are cutting under full load. Exceed that for a while, you'll burn uo the motor. But if you measure at idle, then they'll only draw 5-6 or so amps.
                  Loring in Katy, TX USA
                  If your only tool is a hammer, you tend to treat all problems as if they were nails.
                  BT3 FAQ - https://www.sawdustzone.org/forum/di...sked-questions

                  Comment

                  • LarryG
                    The Full Monte
                    • May 2004
                    • 6693
                    • Off The Back
                    • Powermatic PM2000, BT3100-1

                    #10
                    Originally posted by poolhound
                    The other way to make space is to remove one of the existing breakers and replace with a double like the one below. Now you have a space to put in a 20A breaker.
                    Yep. 'scuse me a minute, I gotta go slap myself in the forehead ...

                    (Pause. OUCH! Okay, I'm back.)

                    ... because I put in just such a breaker (except 15A) for my two lighting circuits when I installed my new subpanel, to save one precious slot and thereby keep me from having to buy a considerably more expensive panel box with the same 80A rating but more spaces. Completely forgot about this option, which is a good one.

                    HOWEVER, you can't install a 20A breaker in place of a 15A breaker unless the existing wiring is 12ga or bigger.
                    Larry

                    Comment

                    • poolhound
                      Veteran Member
                      • Mar 2006
                      • 3195
                      • Phoenix, AZ
                      • BT3100

                      #11
                      Originally posted by LarryG
                      Yep. 'scuse me a minute, I gotta go slap myself in the forehead ...

                      (Pause. OUCH! Okay, I'm back.)

                      ... because I put in just such a breaker (except 15A) for my two lighting circuits when I installed my new subpanel, to save one precious slot and thereby keep me from having to buy a considerably more expensive panel box with the same 80A rating but more spaces. Completely forgot about this option, which is a good one.

                      HOWEVER, you can't install a 20A breaker in place of a 15A breaker unless the existing wiring is 12ga or bigger.

                      LOL


                      I agree 100% with your last point - well made. As long as new cable is run back there this would help Steve make space to fit the appropriate breaker.
                      Jon

                      Phoenix AZ - It's a dry heat
                      ________________________________

                      We all make mistakes and I should know I've made enough of them
                      techzibits.com

                      Comment

                      • LarryG
                        The Full Monte
                        • May 2004
                        • 6693
                        • Off The Back
                        • Powermatic PM2000, BT3100-1

                        #12
                        Originally posted by poolhound
                        As long as new cable is run back there this would help Steve make space to fit the appropriate breaker.
                        Okay, now I get you. Replace *two* existing 15A breakers with one double, and then use the newly-vacated slot for an entirely new circuit, using the desired breaker rating and appropriate wire gauge.

                        Actually, thinking back, I am now pretty sure I used two half-size breakers for my lights. Your link took FOREVER to load, and when it finally did and I saw the price, I thought, "No, I didn't spend THAT much." The breakers I used cost the same three or four bucks as normal full-size breakers.
                        Larry

                        Comment

                        • LCHIEN
                          Internet Fact Checker
                          • Dec 2002
                          • 20920
                          • Katy, TX, USA.
                          • BT3000 vintage 1999

                          #13
                          for my breaker box (GE) it was equipped with half-width breakers which are exactly half the width of the original design breakers. You can install two of them in the space for one old breaker, get twice as mnay circuits.
                          The one Poolhound referred, is two breakers in standard slot. Wow, expensive at $32.50, I think half width breakers were about $4-5 at my Lowes, of course two would cost around $10.

                          then again, $32 is a lot cheaper than changing out the box!
                          Loring in Katy, TX USA
                          If your only tool is a hammer, you tend to treat all problems as if they were nails.
                          BT3 FAQ - https://www.sawdustzone.org/forum/di...sked-questions

                          Comment

                          • Caddis295
                            Forum Newbie
                            • Sep 2004
                            • 51
                            • Williamson, GA.
                            • Ryobi BT3000

                            #14
                            LICHEN is right on the money with the dual c/b set up. I had that very thing done not to long ago.

                            Just a note, your light should be on a separate circuit from the wall outlets. This is to ensure you don't end up in the dark when your tools trip the C/B and you stumble over everything as you go to reset it. (Had that set up once too!)

                            Good Luck.

                            Caddis295
                            Dino "Woodbin Pirate" Gutierrez
                            "The greatest glory is not in never falling but in rising up every time we fall.”

                            Comment

                            • just started
                              Senior Member
                              • Mar 2008
                              • 642
                              • suburban Philly

                              #15
                              One other point, do not put romex in conduit. If you are going to use romex just staple it to a 1x2 glued/screwed to the ceiling. If you want to use conduit then use THHN.

                              Comment

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