Here's a couple to which I don't know the answers:
Situation:
Newly framed IT closet with a vent coming out the top/back which goes to a vent pipe with in-line blower and dampers above the ceiling tiles in an adjacent room. This is of course to remove warm air from the IT closet. The blower is 120V plug in and the dampers are 24V with 120V to 24V transformers, though we may go to a 24V control board when it is all set up.
We want to power the blower and dampers off a battery backup power supply (UPS) that is in the IT closet so that it still runs during short power outages when our computers will still be running. We have run a power supply "Circuit" through the wall from the IT closet to the adjacent room via a 120V 15A flush mount power inlet plug which connects through 1/2" conduit to a 120V 15A receptacle above the ceiling panels in the adjacent room. Into the receptacle we will plug the blower and 24V transformer (or eventually a 120V blower control and 24V damper control). Into the inlet we plug an extension cord that is plugged into the 120V power outlet on the UPS. Power demand is maybe 500 or 600 VA theoretical max, less in practice.
First questions: Do you see any code problems with this? Was the inlet plug and receptacle the correct way to do it as opposed to running an extension cord through a wall?
The inlet plug is 3-prong so the "circuit" from the inlet to the receptacle is grounded when the extension cord is plugged in but since it goes nowhere near a breaker panel it is NOT grounded when the extension cord in unplugged because then it's disconnected from all electrical circuits entirely.
Next questions: Does code require an additional, hard, permanent ground be connected to the "circuit"? If so, does it matter to which raceway/circuit it grounds? For example, if a ground wire were run from a ground screw on the box that holds the receptacle to the ground screw on a nearby junction box that is part of a circuit that powers some other receptacles that are NOT the circuit into which the UPS plugs is that OK? Or must it ground to the same circuit into which the UPS will be plugged? Or should it specifically not be grounded back to any circuit? I couldn't figure this out because I could see arguments for and against each of these connections. Is there code that governs this?
Situation:
Newly framed IT closet with a vent coming out the top/back which goes to a vent pipe with in-line blower and dampers above the ceiling tiles in an adjacent room. This is of course to remove warm air from the IT closet. The blower is 120V plug in and the dampers are 24V with 120V to 24V transformers, though we may go to a 24V control board when it is all set up.
We want to power the blower and dampers off a battery backup power supply (UPS) that is in the IT closet so that it still runs during short power outages when our computers will still be running. We have run a power supply "Circuit" through the wall from the IT closet to the adjacent room via a 120V 15A flush mount power inlet plug which connects through 1/2" conduit to a 120V 15A receptacle above the ceiling panels in the adjacent room. Into the receptacle we will plug the blower and 24V transformer (or eventually a 120V blower control and 24V damper control). Into the inlet we plug an extension cord that is plugged into the 120V power outlet on the UPS. Power demand is maybe 500 or 600 VA theoretical max, less in practice.
First questions: Do you see any code problems with this? Was the inlet plug and receptacle the correct way to do it as opposed to running an extension cord through a wall?
The inlet plug is 3-prong so the "circuit" from the inlet to the receptacle is grounded when the extension cord is plugged in but since it goes nowhere near a breaker panel it is NOT grounded when the extension cord in unplugged because then it's disconnected from all electrical circuits entirely.
Next questions: Does code require an additional, hard, permanent ground be connected to the "circuit"? If so, does it matter to which raceway/circuit it grounds? For example, if a ground wire were run from a ground screw on the box that holds the receptacle to the ground screw on a nearby junction box that is part of a circuit that powers some other receptacles that are NOT the circuit into which the UPS plugs is that OK? Or must it ground to the same circuit into which the UPS will be plugged? Or should it specifically not be grounded back to any circuit? I couldn't figure this out because I could see arguments for and against each of these connections. Is there code that governs this?
