Replies

1. 
   BruceT999 | Jul 08, 2007 08:00pm | #1

   "I was wondering if it's OK to add an outlet along a 25' length of wire running to my exisiting 220V 30A outlet in my shop"

   Yes, you can put additional receptacles on a 220V circuit so long as the loads will not exceed its rated amperage. The problem you will encounter is that the original wiring probably will have been run in Greenfield (armored flex conduit), making it difficult to break into the middle to install a box because the wires will have too little slack to work with. A more likely solution would be to start at the existing 30A receptacle and take off power there, running metal conduit and a new box to where you want your new receptacle. Make sure that your new conduit and box are grounded.

   Be sure to use 10ga wire for red & black because your 30A breaker could allow overheating in smaller gage wire. The existing white may be 12ga, since it is not used for 220V service, only for 110V applications on the appliance. An ideal setup would be a double gang box with a 110V receptacle and a 220V so you can plug in shop vac or other machines as needed. You can also get a 220/110 receptacle [http://www.onestopbuy.com/5031-7609.asp] for a handy way to connect to both voltages in a single gang box.

   BruceT
2. 
   RickChristopherson | Jul 08, 2007 08:31pm | #2

   Yes, you can add another outlet, but you cannot use the outlet as the splice. You must use pigtails from the splice to the outlet. However, in order to do this, you are going to have to come up with about 18 inches of slack in the existing circuit to create a splice. It is a code requirement that all conductors in the junction box extend a minimum of 6 inches from the face of the box for working with.

   If this is a 30 amp circuit, then you must use 30-amp outlets, such as a NEMA 6-30R.

1. 
   BruceT999 | Jul 09, 2007 12:17am | #3

   I don't think you have to use 30 amp outlets on a 30 amp circuit. 20A 110V circuits use both 15A and 20A outlets. A 15A 220 outlet will limit the load that can connect to it by virtue of the plug type it will accept. The important thing is that all wiring be 10ga if the breaker is 30A.
   BruceT

1. 
   RickChristopherson | Jul 09, 2007 06:22am | #4

   No, it is a code requirement that 30 amp devices are used on 30 amp circuits. Just because code permits you to use 15 amp devices on a 20 amp circuit does not automatically translate to other ampacities. The NEC specifically prohibits this on 30 amp circuits.As long as we are on the subject, there is some other information in your previous posting that should be corrected as well. You suggested that the circuit could be split into a 120/240V system, which is true, but you mistakenly stated that the neutral wire in this situation could be #12 wire, and this is not true. All current carrying conductors MUST be sized according to the circuit protection size. If you loaded one leg of the system to its full 30 amp capacity with no load on the other leg, then you would exceed the ampacity of the #12 (20 amp) neutral.Even with that being said, if you were to turn this into a 120/240V system, you would still be required to use 30-amp devices for the 120 volt outlets, and because they are not common for household devices, the circuit would not have much benefit.

   Edited 7/8/2007 11:33 pm ET by RickChristopherson

1. 
   BruceT999 | Jul 09, 2007 08:54am | #5

   I said that the neutral wire in his 30A circuit MAY be 12ga, not that the OP should wire it that way. Apparently I was mistaken about that anyway. I noticed that some stove top pigtails are wired with white wire smaller than the red and black and assumed that it might be that way in the walls too.Thanks for the correction.BruceT