Upgrading Garage Subpanel + Adding 240V

[cls1989]

• I want to make some electrical upgrades to my detached garage. I want to update the subpanel in the detached garage, and I want to add a 240V circuit to the detached garage.
• Electrical Information from the main panel to the detached garage
  • There are two breakers from the main panel inside the house that supply power to the detached garage. A double pole 50-amp breaker and a single pole 20-amp breaker (see breakers with yellow boxes).
  • The wiring for the 50-amp breaker and the 20-amp breaker are routed in two separate pieces of conduit going to the detached garage. See photo below.

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• Sub-panel in the detached garage
  • It’s an old pushmatic breaker box. I believe it’s a 70-amp box. X2 20-amp breakers + x1 30-amp breaker.
  • Only the input from the 50-amp breaker is wired to the subpanel. The input from the 20-amp breaker bypasses the subpanel and goes straight to a junction box. This means the subpanel only controls the circuits associated with the 50-amp input and not the 20-amp input.

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• Goals
  • I want to put the 50-amp and 20-amp wiring into the subpanel box.
  • I want to utilize the 50-amp wiring to incorporate a 240V circuit.
  • Looking for some direction on how I can go about adding 240V to the sub panel and how I can incorporate both sets of wiring into the sub-panel box.
  • What type of subpanel box should I purchase to incorporate both sets of wiring and a 240V circuit?

 

[Megawatt]

• I want to make some electrical upgrades to my detached garage. I want to update the subpanel in the detached garage, and I want to add a 240V circuit to the detached garage.
• Electrical Information from the main panel to the detached garage
  • There are two breakers from the main panel inside the house that supply power to the detached garage. A double pole 50-amp breaker and a single pole 20-amp breaker (see breakers with yellow boxes).
  • The wiring for the 50-amp breaker and the 20-amp breaker are routed in two separate pieces of conduit going to the detached garage. See photo below.

View attachment 112192​

• Sub-panel in the detached garage
  • It’s an old pushmatic breaker box. I believe it’s a 70-amp box. X2 20-amp breakers + x1 30-amp breaker.
  • Only the input from the 50-amp breaker is wired to the subpanel. The input from the 20-amp breaker bypasses the subpanel and goes straight to a junction box. This means the subpanel only controls the circuits associated with the 50-amp input and not the 20-amp input.

View attachment 112186View attachment 112193​

• Goals
  • I want to put the 50-amp and 20-amp wiring into the subpanel box.
  • I want to utilize the 50-amp wiring to incorporate a 240V circuit.
  • Looking for some direction on how I can go about adding 240V to the sub panel and how I can incorporate both sets of wiring into the sub-panel box.
  • What type of subpanel box should I purchase to incorporate both sets of wiring and a 240V circuit?

Sorry for the late reply but you could install a 100 amp main lug only panel and take the 50 breaker out and replace it with a 70 amp double pole breaker. The price of a panel is less than $ 100.00 and purchase a 6 or 8 space panel. Then you could take the wiring loose on the 20 amp breaker. You must keep your equipment grounds and neutrals separate in a sub panel.

 

[cls1989]

Sorry for the late reply but you could install a 100 amp main lug only panel and take the 50 breaker out and replace it with a 70 amp double pole breaker. The price of a panel is less than $ 100.00 and purchase a 6 or 8 space panel. Then you could take the wiring loose on the 20 amp breaker. You must keep your equipment grounds and neutrals separate in a sub panel.

I appreciate the response.

1. You are saying I can install a 100 amp sub-panel in the detached garage?

2. If I’m understanding you correctly you are saying I can replace the 2 pole 50 amp breaker in the main panel with a 2 pole 70 amp breaker? This would allow me to utilize the 70 amps through a single feed and abandon the second 20 amp feed?

3. If I replace the 50 amp breaker with 70 amps wouldn’t I need to run new wiring from the house to the garage? Attached is a photo showing the type of wire that is used for the 50 amp feed. Is this appropriate for 70 amps?



4 With respect to equipment grounds and neutrals can you provide some additional information / a visual?

 

[Megawatt]

I appreciate the response.

1. You are saying I can install a 100 amp sub-panel in the detached garage?

2. If I’m understanding you correctly you are saying I can replace the 2 pole 50 amp breaker in the main panel with a 2 pole 70 amp breaker? This would allow me to utilize the 70 amps through a single feed and abandon the second 20 amp feed?

3. If I replace the 50 amp breaker with 70 amps wouldn’t I need to run new wiring from the house to the garage? Attached is a photo showing the type of wire that is used for the 50 amp feed. Is this appropriate for 70 amps?

View attachment 112241

4 With respect to equipment grounds and neutrals can you provide some additional information / a visual?

Yes you will need to install # 4 wiring times 4 for your 2 hots, 1 neutral and 1 equipment ground. As for keeping the grounds and neutrals separate you will need a ground bar separate from the neutral bar and most main lug panels doesn’t have a ground bar so you will have to purchase one at Home Depot or Lowes. You really need to hire an electrician to assist you with this project.