Acceptable Methods of Motor Lockout - Branch circuit fuse holder inside an industrial control panel?

[petersonra]

A lot of companies do not want to go to the expense of purchasing a safety switch with a normally closed micro switch on motors controlled by drives. Wish the NEC would make it mandatory that at bare minimum when motor is not on the same floor as the drive then the motor must have a local lockable disconnect within 50' & visible from the motor. Would be ok to have disconnects say on water towers to be on the outside. We had 4 water towers with 60 HP motors where they only installed a 30 amp non fixed safety switch to LOTTO motors. I always walked hundreds of feet then climbed thru two door ways to install LOTTO on the drive disconnect.

You got paid by the hour to get some exercise. The company was looking after your health.

 

[don_resqcapt19]

A lot of companies do not want to go to the expense of purchasing a safety switch with a normally closed micro switch on motors controlled by drives. Wish the NEC would make it mandatory that at bare minimum when motor is not on the same floor as the drive then the motor must have a local lockable disconnect within 50' & visible from the motor. Would be ok to have disconnects say on water towers to be on the outside. We had 4 water towers with 60 HP motors where they only installed a 30 amp non fixed safety switch to LOTTO motors. I always walked hundreds of feet then climbed thru two door ways to install LOTTO on the drive disconnect.

How was a 30 amp disconnect ever permitted for a 60 hp motor?

 

[garbo]

How was a 30 amp disconnect ever permitted for a 60 hp motor?

They used it in series with the stop button to lock out tower motors. Told them that besides being a code violation its dangerous for guys that have to go up and change the 3 or 4 V belts every year. Our BSO shop had a guy loose a finger tip when he was replacing belts on a large exhaust fan that he did not LOTTO the motor and motor started up.

 

[don_resqcapt19]

They used it in series with the stop button to lock out tower motors. Told them that besides being a code violation its dangerous for guys that have to go up and change the 3 or 4 V belts every year. Our BSO shop had a guy loose a finger tip when he was replacing belts on a large exhaust fan that he did not LOTTO the motor and motor started up.

A control circuit can never be used as a disconnect or a lockout. The device used for a disconnect or a lockout must physically open the power circuit conductors.

 

[petersonra]

A control circuit can never be used as a disconnect or a lockout. The device used for a disconnect or a lockout must physically open the power circuit conductors.

That is not completely true. You can also use a control safe circuit to lockout a power circuit but I have never seen it done because it is crazy expensive.

 

[garbo]

That is not completely true. You can also use a control safe circuit to lockout a power circuit but I have never seen it done because it is crazy expensive.

Have seen so called safety lockout relay that believe only locked out the control circuit. Would refuse to work on a motor that only used what you termed " control safe circuit ". Too many times I can across contactors & starters that had one or more of the contacts that feed motors welded shut. Years ago we had welders that had to spend a few hours inside of cookers that we had to remove the fuses from safety switch, LOTTO safety switch and remove wires from load side of starter. Both welders, electrician & maintenance boss each installed a lock on LOTTO.

 

[Jraef]

Back to the fuse holders issue: I have seen fuse holders that hinge out and provide a point for locking them in the Open position. The issue that most people miss on those is that they are NOT listed to be opened UNDER LAOD. In other words there must be another means of interrupting current BEFORE you open these devices, i.e. another disconnect (making them pointless) or a contactor. So IF there is a contactor that ALWAYS opens first, then you can in theory use that type of fuse holder as a LO/TO point. But keep in mind that this means opening the enclosure first, and that means having the proper PPE and/or "Live Work Permit" to do so. Or, the entire concept is being done without there being a “Safe Electrical Work Program” document that would pass muster with OSHA.

Seems like a lot of trouble just to save on having a simple disconnect switch...

 

[BillyMac59]

What's wrong with pulling the fuses in the panel then locking access to the panel? Seems unorthodox but is it acceptable to OHSA? I've seen lockout bar attachments for residential type breaker panels. Same sort of thing but larger scale , isn't it?

 

[Jraef]

What's wrong with pulling the fuses in the panel then locking access to the panel? Seems unorthodox but is it acceptable to OHSA? I've seen lockout bar attachments for residential type breaker panels. Same sort of thing but larger scale , isn't it?

What if I come along, see the empty fuse holders and get some fuses to put in there?

 

[BillyMac59]

Panel locked and tagged such that fuse block is not accessible without removing locking bar or otherwise unlocking panel. Like pulling the fuses on a fused disconnect then locking the disconnect door shut.