electricalelectrical-panel
I have an existing 220 line (10-2 wire), that is an outlet for a dust collector.
I need to move the dust collector about 5 more feet down the wall. So the outlet needs to move 5 feet too.
Any problem with taking the plug out of the metal box, using it as a junction box instead, and splicing in another 5 feet of #10 wire to a new outlet down the wall?
I know this is fine with 110 but I don't do much with 220 ever, so just making sure.
NEC 630.11(A) may be of interest.
National Electric Code 2008
ARTICLE 630 Electric Welders
II. Arc Welders
630.11 Ampacity of Supply Conductors.
(A) Individual Welders. The ampacity of the supply conductors shall be not less than the I1eff value on the rating plate. Alternatively, if the I1eff is not given, the ampacity of the supply conductors shall not be less than the current value determined by multiplying the rated primary current in amperes given on the welder rating plate by the factor shown in Table 630.11(A) based on the duty cycle of the welder.
Also take a look at 630.12 Overcurrent Protection.
The Owners manual (PDF) seems to contain the answer.
If we look at 110.14(C) in 2008 NEC, it says:
National Electrical Code 2008
ARTICLE 110 Requirements for Electrical Installations
I. General
110.14 Electrical Connections.
(C) Temperature Limitations. The temperature rating associated with the ampacity of a conductor shall be selected and coordinated so as not to exceed the lowest temperature rating of any connected termination, conductor, or device. Conductors with temperature ratings higher than specified for terminations shall be permitted to be used for ampacity adjustment, correction, or both.
Which means we'll have to check the breakers temperature rating, and the subpanel terminals temperature rating. Then we'll have to look at table 310.16 (Table 310.15(B)(16) NEC 2011), so we can determine the wire size we should use.
In this example image you can see if we're using copper, we'll use 60°C. Once we look at the table, we'll see that for 50A @ 60°C we need 6 AWG copper wire. (50A @ 75°C = 8 AWG).
110.14(C)(1)(a) basically says that if the temperature is not listed, use 60°C for circuits less than 100A. 110.14(C)(1)(b) says if the temperature is not listed, use 75°C for circuits over 100A. However, in the real world 75°C is often used for both.
You cannot cover any junction box that still has live wires in it. Your best bet is to either remove the box all together or just put a cover plate on it. Your other option is to run a new circuit to the new box and de-energize the circuit to the old box and mark the source wires as "NOT IN USE" at your panel in which case I believe you could cover it over.
If there are live wires in the box, sooner or later you will need to get to the box again, which you can't do if you've covered it over! You'll thank yourself later (as will any future home owner).
Best Answer
No problem, that is how you would do it. The only thing you cannot do is to make a splice in a wall and cover it without access to it.
#8 wire sliced onto #10 though might be a problem, not at the splice end, but is your receptacle rated to terminate #8 wire? Why are you increasing the wire size?