machine disconnect

[jdr]

There is a chiller fed directly from a bus duct swing plug 20' above chiller.
The swing plug is the only means of disconnect.
Is this legal? Swing plug is within sight. Is nfpa 79 enforcable, to require a disconnect at a lower level?

 

[iwire]

IMO you need a disconect closer to the unit.

440.14 Location.

Disconnecting means shall be located within sight from and readily accessible from the air-conditioning or refrigerating equipment. The disconnecting means shall be permitted to be installed on or within the air-conditioning or refrigerating equipment.

The disconnecting means shall not be located on panels that are designed to allow access to the air-conditioning or refrigeration equipment.

Exception No. 1: Where the disconnecting means provided in accordance with 430.102(A) is capable of being locked in the open position, and the refrigerating or air-conditioning equipment is essential to an industrial process in a facility where the conditions of maintenance and the supervision ensure that only qualified persons service the equipment, a disconnecting means within sight from the equipment shall not be required.

Accessible, Readily (Readily Accessible). Capable of being reached quickly for operation, renewal, or inspections without requiring those to whom ready access is requisite to climb over or remove obstacles or to resort to portable ladders, and so forth.

 

[petersonra]

There is a chiller fed directly from a bus duct swing plug 20' above chiller.
The swing plug is the only means of disconnect.
Is this legal? Swing plug is within sight. Is nfpa 79 enforcable, to require a disconnect at a lower level?

1.1.1 The provisions of this standard shall apply to the
electrical/electronic equipment, apparatus, or systems of industrial
machines operating from a nominal voltage of 600
volts or less, and commencing at the point of connection of
the supply to the electrical equipment of the machine.

3.3.55 Industrial Machinery (Machine). A power-driven machine
(or a group of machines working together in a coordinated
manner), not portable by hand while working, that is
used to process material by cutting; forming; pressure; electrical,
thermal, or optical techniques; lamination; or a combination
of these processes. Machine can include associated equipment
used to transfer material or tooling, including fixtures,
to assemble/disassemble, to inspect or test, or to package.
[The associated electrical equipment, including the logic controller(
s) and associated software or logic together with the
machine actuators and sensors, are considered as part of the
industrial machine.] [70:670.2]

NFPA79 applies to industrial machines, the definition of which is included in the standard. I don't think a chiller qualifies.

You might have an argument that the required lockout point is the disconnect switch 20 feet above ground and getting to it to put a padlock on it is a little cumbersome.

 

[mdshunk]

It's not likely that an unqualified person will be working on a chiller. I say that the buss plug is fine as the disconnect.

 

[iwire]

It's not likely that an unqualified person will be working on a chiller. I say that the buss plug is fine as the disconnect.

Sure if you ignore the NEC, there are more requirements to the exception than qualified personal.

The Chiller would also have to be essential to an industrial process.

 

[mdshunk]

The Chiller would also have to be essential to an industrial process.

Uh-huh.... and the code does not define essential. If the chiller was for air conditioning of the employees laboring on an industrial process, and they didn't like it hot, the management may call that chiller essential. That "essential" thing is so open to interpretation. I can cause anything to be "essential".

 

[iwire]

That "essential" thing is so open to interpretation.

I agree.

Now is it better to interpret this loosely or tightly?

IMO having the disconect that high up is asking for people to make repairs etc on the chiller without shutting it down.

It appeared to me that the OP wanted a disconect and was looking for code to back it up.

 

[mdshunk]

It is better to have one near the chiller, for sure. If it happens to be fed with buss drop cable, I'd do a pin and sleeve plug and receptacle arrangement. Having it up on the buss duct isn't necessarily going to cause a person to do hot work. I may cause them to hunt down a scissors lift or extension ladder instead, which will increase the repair time.