Control Panel Disconnect with UPS inside

[JimMacD]

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.

 

[petersonra]

wire the output of the UPS in orange wire. that is all that would be required.

 

[petersonra]

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]

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.

Can you comment on NFPA79 5.3.1.1 Section 3 in relation to the main Line disconnect?

-jim

 

[petersonra]

Can you comment on NFPA79 5.3.1.1 Section 3 in relation to the main Line disconnect?

-jim

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)

It says every supply circuit has to have a disconnect. Not much nuance there.

 

[JimMacD]

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)

Is (3) saying that the output of the UPS needs a disconnect?

 

[GoldDigger]

I have the 2012 version:



Is (3) saying that the output of the UPS needs a disconnect?

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.

 

[petersonra]

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.

 

[fmtjfw]

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.

 

[JimMacD]

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.

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