Telescoping Bleachers Disconnect

Status
Not open for further replies.
Sparky2791

Sparky2791

Senior Member
Location
Northeast, PA
Occupation
Electrical Design
I have a project where telescoping bleachers will be used. Manufacturer's engineering department said on the phone they just need a junction box to tie into, a knife switch disconnect is not required. It is a 3 phase circuit, 4 wire, they need the neutral. Their control box holds the thermal overloads and control for the motor which is a 1/2 HP motor. Typically I would just add a disconnect and be done with it but in this case I would have to install it behind the bleachers making it not readily accessible. I cannot install to the side of the bleachers for other reasons.

Does it need a disconnect? I thought I read something in the NEC about fractional HP motors not requiring a disconnect switch.

The panel is not within sight of the bleachers.

Thanks for the reply's!
 
The motor disconnect rules are in 430.102 and are straightforward. Every motor, even a bath ceiling fan requires a disconnect. There is normally a disconnect within sight of the motor and disconnect.
 
tom baker said:
The motor disconnect rules are in 430.102 and are straightforward. Every motor, even a bath ceiling fan requires a disconnect. There is normally a disconnect within sight of the motor and disconnect.
Click to expand...
Got it. Just FYI - the section I was thinking about, which does not apply to my application due to my HP, is 430.109(B).
 
LibertyEngineering said:
I have a project where telescoping bleachers will be used. Manufacturer's engineering department said on the phone they just need a junction box to tie into, a knife switch disconnect is not required. It is a 3 phase circuit, 4 wire, they need the neutral. Their control box holds the thermal overloads and control for the motor which is a 1/2 HP motor. Typically I would just add a disconnect and be done with it but in this case I would have to install it behind the bleachers making it not readily accessible. I cannot install to the side of the bleachers for other reasons.

Does it need a disconnect? I thought I read something in the NEC about fractional HP motors not requiring a disconnect switch.

The panel is not within sight of the bleachers.

Thanks for the reply's!
Click to expand...
Can't you just use a 3 pole motor rated switch instead of a NF disco? Or, worst case, use a lock off device on the breaker.
 
Don't forget the requirements of 430.102(A) for the controller. It sounds as if you will need a disconnect in sight from the controller.

(Maybe not Code but it sure seems reasonable to have an in-sight disconnect on moving bleachers)
 
Knightryder12 said:
Can't you just use a 3 pole motor rated switch instead of a NF disco? Or, worst case, use a lock off device on the breaker.
Click to expand...
Sure could use a motor rated switch. Not sure a lock off device would comply with NEC disconnect requirements. Has to be within site and if it is no need for the lock off.
 
tom baker said:
The motor disconnect rules are in 430.102 and are straightforward. Every motor, even a bath ceiling fan requires a disconnect. There is normally a disconnect within sight of the motor and disconnect.
Click to expand...
Look at exception #3. As long as the device is lockable, it is not required to be within site. I have never seen, designed or installed a disconnect on telescoping bleachers ever and have just put a lockable device on the breaker.
 
Exception 3 is for a vam (2017). I was commenting a disconnect is required for the motor. Often one disco can be used for motor and controller
 
Status
Not open for further replies.
Top