Switch horsepower rating question

[javyLSU]

I was doing some annual maintenance on my Twin Busch scissor lift, and noticed that the plate specifies the motor as a 3HP motor running on 120 VAC. When I installed the dedicated 20A run for the lift, I installed a Leviton 1221-PLR 20A switch at the receptacle. The switch was not installed to do any start/stop functions for the lift motor, it was installed to kill power to the receptacle when I’m finished using the lift to add another (currently out of reach) obstacle my kids would have to overcome to power on the lift. I never gave thought to matching the HP rating of the switch to the lift motor.

I did a little reading on Mike Holt, and have come away with the understanding that only when the device is being used as the motor controller (e.g. it performs start-stop functions) does the switch need to be HP rated.

Given that the switch I’ve installed does not perform such a function, does it matter that my switch is only rated for 1HP? Thanks for any help!

 

[Davefr]

I was doing some annual maintenance on my Twin Busch scissor lift, and noticed that the plate specifies the motor as a 3HP motor running on 120 VAC. When I installed the dedicated 20A run for the lift, I installed a Leviton 1221-PLR 20A switch at the receptacle. The switch was not installed to do any start/stop functions for the lift motor, it was installed to kill power to the receptacle when I’m finished using the lift to add another (currently out of reach) obstacle my kids would have to overcome to power on the lift. I never gave thought to matching the HP rating of the switch to the lift motor.

I did a little reading on Mike Holt, and have come away with the understanding that only when the device is being used as the motor controller (e.g. it performs start-stop functions) does the switch need to be HP rated.

Given that the switch I’ve installed does not perform such a function, does it matter that my switch is only rated for 1HP? Thanks for any help!

Yes, It needs to be rated just like your other switch because the surge of current when the motor turns on passes thru BOTH switches. Inductive loads need more robust switch contacts due to surge current considerations.

 

[wyliesdiesels]

Youre using it as a disconnect and therefore needs to be rated for the same or greater HP as the motor.

I dont know of any snap switches that are rated for 3HP at 120v so I would suggest looking at non-fused A/C pull out disconnects.

 

[nadogail]

Youre using it as a disconnect and therefore needs to be rated for the same or greater HP as the motor.

I dont know of any snap switches that are rated for 3HP at 120v so I would suggest looking at non-fused A/C pull out disconnects.

What he said, non-fused pull out disconnects are IMHO, inexpensive.

 

[javyLSU]

Thanks for the advice everyone.

 

[u2slow]

If this motor/device is factory corded with a 5-15p or 5-20p it is not 3hp.

Kind of like my '6hp' shop vac....

 

[javyLSU]

If this motor/device is factory corded with a 5-15p or 5-20p it is not 3hp.

Kind of like my '6hp' shop vac....

It is 5-20P corded - the specs for the lift rate it at 16A on 110V. Would I then be ok continuing to use my 20A/1HP-rated switch? Thanks again for your input.

 

[Norcal]

It is 5-20P corded - the specs for the lift rate it at 16A on 110V. Would I then be ok continuing to use my 20A/1HP-rated switch? Thanks again for your input.

110V? Looks to be ChiCom ****.

 

[u2slow]

It is 5-20P corded - the specs for the lift rate it at 16A on 110V. Would I then be ok continuing to use my 20A/1HP-rated switch? Thanks again for your input.

A 16A/120V motor is ~1HP. You are fine.

The next step up is something like this... its rated for 2HP @ 120V.

https://www.leviton.com/en/products/ms303-ds

 

[wyliesdiesels]

It is 5-20P corded - the specs for the lift rate it at 16A on 110V. Would I then be ok continuing to use my 20A/1HP-rated switch? Thanks again for your input.

yeah no way is that 3HP.

What does the motor nameplate say? SPL?

16a is about 1hp

company should be sued for false advertising

 

[javyLSU]

This is what the nameplate shows:

 

[u2slow]

This is what the nameplate shows:

That's a goofy nameplate since it doesn't list the full-load amps. Maybe something is lost is translation? A domestic german motor would be using 220V @ 50Hz.

2.2kW is very close to 3hp, in which case it would draw around 34A @ 115V (per the table.)

If it were my equipment, I would test-run it on a suitably large circuit and see what it actually draws with a clamp ammeter.

 

[javyLSU]

I thought the same thing when I saw it... I did put an amp clamp on the hot line when I first ran it last year, and the most it pulled under load was 17 amps. I have a dedicated 20 amp run for this lift, and it's never tripped the breaker either. That's why I never gave thought to a higher rated switch...

 

[wyliesdiesels]

yeah nameplate makes no sense

110v is NOT 60hz

It says designed for germany which would be 50hz.

 

[javyLSU]

A funny thing happened today - I was cleaning my garage and noticed a nameplate still attached to the lift motor - the previous picture I posted was a nameplate that i found on the floor next to the lift control box. I assumed it fell off the motor, but there’s a different nameplate still attached. For posterity’s sake (and for anyone else that might be researching this lift) here is the nameplate that is actually attached to the motor: