Electrical – Hard wiring condensate pump with ground to furnace with only hot / neutral

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Current condesate pump pigtails for hot and neutral onlyMy 1996 oil burning air handler has a hard wired condensate pump for AC that recently died. Newer condensate pumps all seem to plug into the wall via a three prong plug. I do not have an outlet near the furnace (the house is all armored cable), so planed to strip the power cord from the new condensate pump and hard wire it to the furnace as was done with the existing pump. HOWEVER, when I opened up the junction box inside the furnace, there is only a hot and neutral connection (again goes to armored cable to the furnace motor). Can I connect hot to hot and connect neutral + ground to neutral to complete the circuit? Is there any other process to attach the ground wire from the new pump? It's hard to see but the green wire running to the motor is attached to a screw in the back of the box. Can I attach the ground under the screw too? close up inside boxThanks!!

Best Answer

Use a pigtail for the ground and a cord grip for the cord

With the power off:

  1. Fit the cord grip (a Cooper/Crouse-Hinds NCG50-50 will do the trick) to a knockout in the box using a matching locknut and run the cut-off cord end through it, then tighten the cord grip down. This provides strain relief and sealing for the cord connection, which is permitted here by NEC 400.7(A) point 7 (preventing the transmission of vibration; in this case, from the pump to the rest of the furnace).
  2. Wire the cord hot to the furnace hot, and the cord neutral to the furnace neutral
  3. Remove the existing wire from the ground screw, and nut it together with a length of bare 12AWG as well as the ground from the cord
  4. Land the length of bare 12AWG (this is a pigtail for the ground) on the existing ground screw in the box
  5. Button it all up and turn the power back on
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