Grinder pump wiring

[kwired]

Not really a septic but similar. It's just a holding tank before it gets pumped into the city sewer system

Most call that a lift station.

A common method for household grinder pumps here is 12x12 PVC box with a receptacle mounted inside and a 2" PVC nipple to the pump well. The plug and associated float adapter are pulled thru the 2" and plugged in to the box receptacle. The 2" is sealed with various compounds.

You mentioned earlier that locally you do accept that plug as the disconnecting means. Strictly based on NEC though I fail to see how that meets the requirements for motor and/or controller disconnecting means if it is inside that enclosure. Wouldn't it only be "in site from" when that enclosure is opened?

Would you accept cord and plug connections as disconnecting means for any other motors/controllers if they were all located inside an enclosure on the supply side of each motor controller with no external operating means?

 

[Smart $]

Most call that a lift station.

You mentioned earlier that locally you do accept that plug as the disconnecting means. Strictly based on NEC though I fail to see how that meets the requirements for motor and/or controller disconnecting means if it is inside that enclosure. Wouldn't it only be "in site from" when that enclosure is opened?

Would you accept cord and plug connections as disconnecting means for any other motors/controllers if they were all located inside an enclosure on the supply side of each motor controller with no external operating means?

How would that be any different than a breaker of a panelboard with a front-cover door? Just leave the door or enclosure cover open and its within sight.

 

[GoldDigger]

:thumbsup:
It is important that the disconnect be visible to you when it is open. Not much need to be able to see it before you set out to open it. As long as it is safe to enter the chamber before you disconnect the motor and start working on it.
There is a world of difference between "in sight" and "readily accessible".

Sent from my XT1080 using Tapatalk

 

[kwired]

How would that be any different than a breaker of a panelboard with a front-cover door? Just leave the door or enclosure cover open and its within sight.

I see your point, but also consider with the panelboard the breakers are able to be operated without removing the dead front. I think what I was trying to get at was to question whether or not it would be acceptable to open an enclosure and expose the operator to live parts while performing a disconnecting task, which is what I understand the situation to be in the OP as well as what Gus says they accept locally.

 

[GoldDigger]

... I think what I was trying to get at was to question whether or not it would be acceptable to open an enclosure and expose the operator to live parts while performing a disconnecting task,....

A good point, but perhaps in practice the power will be turned off at a more remote breaker or disconnect while the enclosure is opened. Then the disconnected plug will be in sight as required for operations on the motor or other equipment.
Not clearly meeting the wording or intention of the Code, but close enough that some AHJs might be OK with it.

 

[Smart $]

I see your point, but also consider with the panelboard the breakers are able to be operated without removing the dead front. I think what I was trying to get at was to question whether or not it would be acceptable to open an enclosure and expose the operator to live parts while performing a disconnecting task, which is what I understand the situation to be in the OP as well as what Gus says they accept locally.

I'm thinking there are no exposed live parts inside the enclosure... at least upon taking the cover off. Consider a properly wired receptacle in a box (or cord with female cord cap) and plug-and-cord from the equipment. Now take that, and put it an enclosure and seal it where the cables/cord enter the enclosure.

 

[kwired]

A good point, but perhaps in practice the power will be turned off at a more remote breaker or disconnect while the enclosure is opened. Then the disconnected plug will be in sight as required for operations on the motor or other equipment.
Not clearly meeting the wording or intention of the Code, but close enough that some AHJs might be OK with it.

My reply to that is what was the point of removing the exception a few code cycles back that allowed a locking means at a remote controller location if you have to disconnect the remote location first anyway?

 

[renosteinke]

"2. "How does the plug get into the box?"
Simple: You bring the wire into the box through a seal fitting, attach the plug to it, place the plug into the receptacle and put the sealing cover back on the box. It is a large box. "

Seems to me that putting the plug into a bolted and gasketed enclosure and having to attach the plug cancels out any possible advantage there might be to using a plug. Sort of like 'walking barefoot' inside a pair of hip waders.

 

[GoldDigger]

"2. "How does the plug get into the box?"
Simple: You bring the wire into the box through a seal fitting, attach the plug to it, place the plug into the receptacle and put the sealing cover back on the box. It is a large box. "

Seems to me that putting the plug into a bolted and gasketed enclosure and having to attach the plug cancels out any possible advantage there might be to using a plug. Sort of like 'walking barefoot' inside a pair of hip waders.

Maybe. But at least at the end of the process you have a disconnect that can be used just by opening the box.
The idea of threading the assembled plug through a 2" nipple and then packing/sealing around the cord sounds better to me in hindsight.
Maybe the pump manufacturer supplies the cord with a plug and a 2" threaded connector on the end. Then you just tighten the sealing gland around the cord once you have the fitting threaded in?

 

[kwired]

I myself would rather see a watertight plug and connector outside the enclosure for a motor disconnect. Now if the controller is in that enclosure then you still need a controller disconnect.

I think this is a potential place to apply the exception allowing remote disconnecting means where lockable that follows 430.102(B)(2) and in particular sub part (a) in the exception which says:"Where such a location of the disconnecting means for the motor is impracticable or introduces additional or increased hazards to persons or property"

Now that doesn't mean all AHJ will agree with this, but is better chance here than many other motor applications.
Add: Placing a disconnect on a post near the tank may not be all that desirable, but is not impracticable or generally wouldn't increase any hazards either.