enter image description here enter image description here I have a breaker panel with one open breaker. Problem is I was going to add a heat pump to my seasonal cottage but it requires 220. Will I need to replace entire panel to accommodate this heat pump? It's a 100 amp max box as well. Cottage is 1200 square feet. Don't know the code for this rural town in Maine. Will need to get this. Thanks

  • What make/model is the panel, and can you post photos of it please? – ThreePhaseEel Nov 27 '16 at 21:46
  • Where are you on this planet? Also, how many square feet is said cottage, and how many kitchen small appliance branch circuits do you have? – ThreePhaseEel Nov 27 '16 at 21:47
  • Can you get us less-grainy shots of the panel itself + the label on the inside of the door? – ThreePhaseEel Nov 29 '16 at 0:35
  • We also need to know the square footage of the cottage (the Code lighting load calculations are based on that) – ThreePhaseEel Nov 29 '16 at 0:37
  • Can you list off the labels for the right side breakers below "RANGE", and for the bottom left occupied breaker as well? – ThreePhaseEel Nov 29 '16 at 2:18

It looks like your old Westinghouse panel will accept breakers from Eaton or Cutler-Hammer (but check at place of purchase). If so, this tandem breaker can serve two circuits but use only one slot in the panel. enter image description here

This is different from a double pole breaker which takes two slots like you would need for a 240 volt appliance: enter image description here

To use the tandem, pull out a pair of single pole/non-tandem breakers (and discard), connect the two circuit wires to the tandem and insert. Voila! You have freed up an extra slot.


Depends on your other loads/circuits.

You might be able to combine some things and free up a second breaker, but the total load will matter quite a bit; and you might NOT be able to combine things, depending on what you have.

If the total load capacity and service capacity of the present panel allows, you might be able to relocate some circuits to a sub-panel. If you shift 3 or more circuits to a sub-panel you'll lose two spaces for the sub-panel feed but gain enough spaces for your heat-pump in the main panel. But this is pointless if the loads exceed the panel capacity.

Then again, some panels ("Federal Pacific Stab-Lok" for example) simply should be replaced (even if you are not adding loads.)

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