Install 20A outlet

[ollie76]

Afternoon folks, looking for some advice and I am wondering if what I'm planning is against the rules or code?

I'd like to install a 20A outlet in my attached garage. Currently, all the plugs around the garage are 15A . I'd like to find the first outlet in the run and replace the wiring to it with the larger size wire and then put in the new outlet along with a 20 A breaker.

The remaining regular 15A outlets would then be re-attached to the circuit as before.

 

[Zeke]

No, that's not the way to do it. You have to protect the circuit by the smaller wire size. If you have 12 ga wire through out the circuit then it's OK to install the 20A outlet and breaker. But, if you have a 15A breaker and 14 ga wire, you must stay at a 15A breaker.

NEC 240.4(D)(3) states that 14 AWG must be protected at 15A. You can not use 14 AWG anywhere on a circuit that has a 20A breaker.

A 20a breaker on 14 ga wire is under protected.

edit: That code was taken from the 2008 NEC but it still stands. There are always some weird exceptions and this forum will find them, but the gist of it is don't do it.

 

[ollie76]

Makes sense! Figured as much, thanks for the info.

Probably best to replace all the wire in the run with 12 ga and replace just the single outlet huh?

Would it be possible to pull new wire through using the old wire or is this stuff secured behind the walls somehow? These are finished walls in my garage.

 

[Zeke]

Makes sense! Figured as much, thanks for the info.

Probably best to replace all the wire in the run with 12 ga and replace just the single outlet huh?

Would it be possible to pull new wire through using the old wire or is this stuff secured behind the walls somehow? These are finished walls in my garage.

All romex and metal clad cable is stapled close to the box. You would have a very hard time using the old wire to fish in a new one. If you can plan on some drywall repair you may find a good deal of the runs from box to box are just pulled through drilled holes in the studs. But, it goes up and down and you'd often by pulling the wire at an extreme angle to the orientation of the hole.

And if any wires run along a framing member, they will be stapled every 6 feet.

You might consider running a chase at the ceiling and dropping down to surface mounted boxes through conduit or Wire Mold. Or if there is an accessible attic space above, you can likely fish strait down in the stud cavity. There will be some blocking that you will encounter.

Some drywall repair is inevitable.

 

[Rock knocker]

Stapled to the studs.

You could do a new run of 12ga surface ran in EMT conduit

 

[Notgrownup]

That is why I am wiring my whole shop with 12 gauge... I am going to use 20a throughout ...

 

[Stuart in MN]

Do you have a specific need for a 120vac, 20 amp receptacle? Very few tools or appliances use them.

You didn't mention where you live, but the National Electric Code in the US allows 15 amp receptacles to be used on a 20 amp circuit, as long as there are two or more, and a standard duplex receptacle counts as two.

 

[ollie76]

Yeah my welder is a 20 amp model.

 

[Zeke]

Do you have a specific need for a 120vac, 20 amp receptacle? Very few tools or appliances use them.

You didn't mention where you live, but the National Electric Code in the US allows 15 amp receptacles to be used on a 20 amp circuit, as long as there are two or more, and a standard duplex receptacle counts as two.

Using 15 A rated outlets is not the same as underprotecting a branch circuit.

Ollie, do this: install a dedicated 20 A or even higher outlet for the welder. Since you planed on replacing the wiring from the panel to the first outlet, I assume you can also run a new circuit.

Welders work fine on extension cords as long as they are heavy gauge and rated for what the circuit is. So, for instance, you could install a 30 A 120 v receptacle and use a 10 ga cord easily 50 feet or more. You could get away with 20 A and a good 12 ga. cord for 50 feet. Use the proper connections as most extension cord ends are rated for 15 amps even if the wire gauge inside is 12 ga.

It's not a good practice but you can even string out some romex cable from wall to welder. The difference between extension cords and house wiring is stranded wire v. solid, the ext cords are flexible. They are also wrapped better for being stepped on and driven over. But if it's just you, well....

 

[Speedy Petey]

Yeah my welder is a 20 amp model.

Why not just run a new dedicated circuit to a new receptacle and leave the existing??

 

[sberry]

Agree, add a circuit.

 

[C96]

No, that's not the way to do it. You have to protect the circuit by the smaller wire size. If you have 12 ga wire through out the circuit then it's OK to install the 20A outlet and breaker. But, if you have a 15A breaker and 14 ga wire, you must stay at a 15A breaker.

NEC 240.4(D)(3) states that 14 AWG must be protected at 15A. You can not use 14 AWG anywhere on a circuit that has a 20A breaker.

A 20a breaker on 14 ga wire is under protected.

edit: That code was taken from the 2008 NEC but it still stands. There are always some weird exceptions and this forum will find them, but the gist of it is don't do it.

Be careful with that Zeke, the last time I tried quoting from the NEC I got the Miranda Warning from pattenp and then escorted off!

I understand the purpose of the table, I was simply commenting on the fact that #10 THHN has an allowable ampacity of 40. The comment was not meant to imply anything other than that.

 

[ollie76]

I know you guys are right. Adding a circuit is the way to go.....its just that the finished walls are making that option difficult

 

[ollie76]

Right so in my garage, the breaker panel is on the wall where I would like my 20A outlet. I would estimate the wire would be 6-8 ft in length. Could I run some kind of armored cable secured to the outside of the wall to a new outlet?

 

[James-W]

Right so in my garage, the breaker panel is on the wall where I would like my 20A outlet. I would estimate the wire would be 6-8 ft in length. Could I run some kind of armored cable secured to the outside of the wall to a new outlet?

I am not an electrician but I am pretty sure you can use conduit on the outside of the wall and run it wherever you need it to go. I guess you could even use the plastic conduit if it meets the code for your area.

 

[ollie76]

That sounds just right....will look into the code