[barryb38583]

A novice here...

Have a shed with current 115v service. I want to go to 220 using 12/2. My understanding is, black and white wires go together and then you have the (bare) ground.

My current recepticles are 115 ( I think) two poles on each side. I believe the ground is pigtailed.

My questions, given I only have two wires to connect..

1) How do I pass through the recepticles with service?

2) I need to put a GFIC on the front of the leg... how do I wire for that?

I've got a Cutler-Hammer BR220 120/240 2 pole breaker.

Thanks Very Much Barry

[Stratmando]

You can change the breaker and shed to 240 volts, problem is you woun't have any 120 volts as you have no neutral.
If you need both, you will need to upgrade wiring, more, and or bigger.

[stanfortyman]

Barry, why do you want to "go to 220"??
Are you adding a new 240v circuit and leaving the existing 120v circuit?
What is this new 240v circuit for?

You CANNOT have both 240v and 120v using only a 12/2 cable. That 12/2 can be either 120v or 240v. NOT both.

[stanfortyman]

Re-reading I see what you want to do. You cannot with the 12/2. You need 12/3 in order to do what you want.

[barryb38583]

Sorry guys, I meant, go to 20a service using my existing 15a 12/2 wiring.

A novice here......

Have a shed with current 115v service. I want to go to 20amps using 12/2. My understanding is, black and white wires go together and then you have the (bare) ground.

My current recepticles are 115 ( I think) two poles on each side. I believe the ground is pigtailed.

My questions, given I only have two wires to connect..

1) How do I pass through the recepticles with service?

2) I need to put a GFIC on the front of the leg...how do I wire for that?

I've got a Cutler-Hammer BR220 120/240 2 pole breaker.

Thanx Very Much Barry

[donf]

New to this thread. Assumption: This is a Remote shed, it is not attached to the residence.

Let's get some real basic information for the original poster.

Most household cabling is listed for 600 VAC or less.

Electricity is distributed to the residence through a Lateral (below ground) or service drop (above Ground)

The power company provides 240 VAC to the residence via 2 ungrounded (hot) conductors and 1 grounded (Neutral) conductor.

These conductors in turn feed the two hot phases of the main panel and the one Neutral connection. The Neutral conductor is "Bonded" (electrically joined) together, then the panel is grounded via an equipment grounding conductor to either grounding rods or the cold water pipe.

Most homes would use a 14/2 cable to feed a standard 15 amp receptacle. Black is connected to the darker screw and white is connected to the silver screw terminal.

Now given all of above, let's explore what you may be trying to do in your shed.

To bring 240 VAC to the shed, you need to use two tandem breakers inside the main panel box. Each 20 amp Breaker and using the same handle. You must use a 12/3 with ground cable to carry the power to the shed.

At the shed, you must attach each hot conductor (Black and Red) to a Phase Lug connector. The White (Grounded Conductor or Neutral) connects to the Neutral bus. It must be isolated from the subpanel grounding system.

Now you can start to fan out your shed's wiring to at least one light. The receptacles must be GFCI protected.

[ohb0b]

Have a shed with current 115v service. I want to go to 20amps using 12/2. My understanding is, black and white wires go together and then you have the (bare) ground.

My current recepticles are 115 ( I think) two poles on each side. I believe the ground is pigtailed.

My questions, given I only have two wires to connect..

1) How do I pass through the recepticles with service?

2) I need to put a GFIC on the front of the leg...how do I wire for that?

I've got a Cutler-Hammer BR220 120/240 2 pole breaker.

Thanx Very Much Barry

Still doesn't make sense. You have a 120 volt branch circuit going to the shed, wired in 12/2 wire. (I'm assuming a buried UF cable, 12-2G)

If you simply want 20 amps at 120 volts, no. 12 AWG is rated for 20 amps. The only reason someone would run No. 12 for 15 amps is either for voltage drop if it is a long distance, or if they happened to have some laying around and decided to use it.

But... you have a 2-pole breaker, which means you are considering 240 volts. You have existing 120 volt receptacles you want to keep, so you need a neutral. This means you have more than one branch circuit, so you need a sub-panel in the shed.

You can't do this with 12-2 cable. You need 4 wires to be code compliant. (Two hots, a neutral, and a ground)

As far as putting a GFCI in the circuit. Determine which is the first receptacle in line. Wire the "home run" into the LINE side terminals on the GFCI. Connect the wires leading to the other receptacles into the Load terminals.