Control Panel Disconnect with UPS inside

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JimMacD

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I'm designing a 120VAC control panel that contains a 1500VA, 120V UPS (Allen Bradley 1609-D). I am providing a flange-mounted disconnect handle to switch the main MCCB and remove incoming power from the panel, however, this alone will not disconnect the UPS output (it will be on battery power) - thus the controls circuit stays live. My plan was to have a AUX contact from the MCCB switch the UPS systems "Remote ON/OFF" dry contact (Pins 7/8), which will turn off the output of the UPS system. Will this comply with NFPA79?<br><br>Thank you for the help.
 
Incidentally, attempting to use the remote on/off contact as a disconnecting means will fail the UL508a test for what you are allowed to use as a disconnecting means.
 
JimMacD said:
Can you comment on NFPA79 5.3.1.1 Section 3 in relation to the main Line disconnect?

-jim
Click to expand...

The latest version I have is 2002. We do not use it all that much.

Is this what you are referring to?

5.3.1.1 A supply circuit disconnecting means shall be provided
for the following:
(1) Each incoming supply circuit to a machine
(2) The supply circuit to a feeder system using collector wires,
collector bars, slip-ring assemblies, or flexible cable systems
(reeled, festooned) to a machine or a number of machines
(3) Each on-board power source (e.g., generator)
Click to expand...

It says every supply circuit has to have a disconnect. Not much nuance there.
 
I have the 2012 version:

5.3.1.1
A supply circuit disconnecting means shall be provided
for the following:
(1) Each incoming supply circuit to a machine
(2) The supply circuit to a feeder system using collector wires,
collector bars, slip-ring assemblies, or flexible cable systems
(reeled, festooned) to a machine or a number of machines
(3) Each on-board power source (e.g., generators, uninterruptible
power supplies)
Click to expand...

Is (3) saying that the output of the UPS needs a disconnect?
 
JimMacD said:
I have the 2012 version:



Is (3) saying that the output of the UPS needs a disconnect?
Click to expand...
I would read it that way, yes.

The remote shutoff may be handy to disable the UPS before opening the cover of the enclosure, but before working on the internal wiring I would say that you need to have a physical disconnect (which could be a plug and socket connector) to meet the requirements of 5.3.1.1 and then use it.
 
After thinking about this, I am pretty sure you need some way to disconnect the UPS output power.

It does not have to be associated with the cabinet disconnect though.

Hope I caught this before anyone quoted part of what I previously said.
 
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PLEASE for safety's SAKE

PLEASE for safety's SAKE

If the UPS powers powers ANY wires that leave the control box please! PLease! PLEASE! put a bloody big sign on the cabinet that states connected wires may be energized when incoming power is off!

I know of at least 1 elevator controller that powers the CB tripped alarm contact from a UPS inside the cabinet.
 
petersonra said:
After thinking about this, I am pretty sure you need some way to disconnect the UPS output power.

It does not have to be associated with the cabinet disconnect though.

Hope I caught this before anyone quoted part of what I previously said.
Click to expand...


UPS outputs will go immediately to circuit breakers which can disconnect all load from the UPS. No UPS load wires will be leaving the control panel.

Jim
 
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