Hot work on UPS equipment

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bravo69

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Hello,

Does anyone know if hot work is permitted on UPS equipment? I was told it was once allowed by OSHA but now the code changed where it cant be done. If you can point me in the right direction that would be great.

Thank you in advance
 
bravo69 said:
Hello,

Does anyone know if hot work is permitted on UPS equipment? I was told it was once allowed by OSHA but now the code changed where it cant be done. If you can point me in the right direction that would be great.

Thank you in advance
Click to expand...

hot work is permitted on UPS equipment under the same conditions as any other piece of equipment. The basic rule is NO HOT WORK. There are some minor exceptions such as for debugging if it can be done safely.
 
https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9910

1910.333(a)(1)
"Deenergized parts." Live parts to which an employee may be exposed shall be deenergized before the employee works on or near them, unless the employer can demonstrate that deenergizing introduces additional or increased hazards or is infeasible due to equipment design or operational limitations. Live parts that operate at less than 50 volts to ground need not be deenergized if there will be no increased exposure to electrical burns or to explosion due to electric arcs.

Note 1: Examples of increased or additional hazards include interruption of life support equipment, deactivation of emergency alarm systems, shutdown of hazardous location ventilation equipment, or removal of illumination for an area.

Note 2: Examples of work that may be performed on or near energized circuit parts because of infeasibility due to equipment design or operational limitations include testing of electric circuits that can only be performed with the circuit energized and work on circuits that form an integral part of a continuous industrial process in a chemical plant that would otherwise need to be completely shut down in order to permit work on one circuit or piece of equipment.

Note 3: Work on or near deenergized parts is covered by paragraph (b) of this section.
 
ron said:
https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9910

1910.333(a)(1)
"Deenergized parts." Live parts to which an employee may be exposed shall be deenergized before the employee works on or near them, unless the employer can demonstrate that deenergizing introduces additional or increased hazards or is infeasible due to equipment design or operational limitations. Live parts that operate at less than 50 volts to ground need not be deenergized if there will be no increased exposure to electrical burns or to explosion due to electric arcs.

Note 1: Examples of increased or additional hazards include interruption of life support equipment, deactivation of emergency alarm systems, shutdown of hazardous location ventilation equipment, or removal of illumination for an area.

Note 2: Examples of work that may be performed on or near energized circuit parts because of infeasibility due to equipment design or operational limitations include testing of electric circuits that can only be performed with the circuit energized and work on circuits that form an integral part of a continuous industrial process in a chemical plant that would otherwise need to be completely shut down in order to permit work on one circuit or piece of equipment.

Note 3: Work on or near deenergized parts is covered by paragraph (b) of this section.
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Ron, has OSHA code changed in the last few years? It was brought to my attention that hot work was allowed and now revisions say its not permitted. The UPS equipment supports life safety, PLC & Network cabinets. The life safety fire alarm system would be increased hazards and therefore hot work is permitted, correct?
 
bravo69 said:
Ron, has OSHA code changed in the last few years? It was brought to my attention that hot work was allowed and now revisions say its not permitted. The UPS equipment supports life safety, PLC & Network cabinets. The life safety fire alarm system would be increased hazards and therefore hot work is permitted, correct?
Click to expand...

The rules have remained pretty much the same. Education and enforcment has been increasing.

The fire alarm has its own battery back up.
 
Almost all the work can be done with the unit de-energized (at the last place I worked) with some control type adjustments that could only be done with the unit energized. Do you have a global wrap to completely bypass the UPS?
 
bravo69 said:
Hello,

Does anyone know if hot work is permitted on UPS equipment? I was told it was once allowed by OSHA but now the code changed where it cant be done. If you can point me in the right direction that would be great.

Thank you in advance
Click to expand...

the default is the only time working something hot is permitted,
is when it's more hazardous to de-energize it.

i've only had that situation once, about 35 years ago.
a 2000 amp transfer switch in a hospital welded its contacts
togeather due to a phase shift between shore power, and the
genset, during weekly testing.

all the life support in the hospital was on a genset, and couldn't
be changed back to poco. if the genset went off, so did life support
in the hospital, ER, OR's, etc.

so, we put jumpers around the contacts, and removed the contact blocks and
changed them out hot, then tested the switch with it jumpered, reset it,
and removed the jumpers.

so i was backup for the factory tech. we drew up a written plan, talked it thru
a couple times, went up to unused beds on an upper floor, slept till 1 am, and
did it then.

35 years ago, no arc flash suits. leather gloves, kneeling on pads.
really couldn't blanket things and still get to them.

in todays world, it would be done a lot different.
 
I think the operative issue is, the rules don't change just based on the SOURCE of the electricity. So if a UPS is on an putting out power, it's hot work.

A long time ago I witness someone get electrocuted by DC power stored in a cap bank on a large DC drive... All the switches were off, he just apparently forgot that the caps store a lot of energy (or got complacent because he had been doing it for 25+ years).
 
bravo69 said:
Ron, has OSHA code changed in the last few years? It was brought to my attention that hot work was allowed and now revisions say its not permitted. The UPS equipment supports life safety, PLC & Network cabinets. The life safety fire alarm system would be increased hazards and therefore hot work is permitted, correct?
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You can rationalize it any way you like to make it work in the way you want it to work.

Although UPS batteries stay energized, hard to imagine that if it was turned off in the right conditions and timeframe, that it would be more hazardous to turn off than if you worked on it hot.

There are often other ways around working it hot, depending on what system or connections you are working on. Generally bypass' or temp connections get rid of the need to what was considered in the past was a reason to work hot.
 
ron said:
https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9910

1910.333(a)(1)
"Deenergized parts." Live parts to which an employee may be exposed shall be deenergized before the employee works on or near them, unless the employer can demonstrate that deenergizing introduces additional or increased hazards or is infeasible due to equipment design or operational limitations. Live parts that operate at less than 50 volts to ground need not be deenergized if there will be no increased exposure to electrical burns or to explosion due to electric arcs.

Note 1: Examples of increased or additional hazards include interruption of life support equipment, deactivation of emergency alarm systems, shutdown of hazardous location ventilation equipment, or removal of illumination for an area.

Note 2: Examples of work that may be performed on or near energized circuit parts because of infeasibility due to equipment design or operational limitations include testing of electric circuits that can only be performed with the circuit energized and work on circuits that form an integral part of a continuous industrial process in a chemical plant that would otherwise need to be completely shut down in order to permit work on one circuit or piece of equipment.

Note 3: Work on or near deenergized parts is covered by paragraph (b) of this section.
Click to expand...


I know this is an old thread but I have a question about this. 'Live parts to which an employee may be exposed' If I am working in a live panel, for troubleshooting purposes only, meters etc, and if everything in the panel is touch safe to the point that you would be unable to physically touch a line voltage terminal (with fingers or any other body part), would that classify the situation to a condition of where the employee would not be able to be exposed?
 
Aleman said:
I know this is an old thread but I have a question about this. 'Live parts to which an employee may be exposed' If I am working in a live panel, for troubleshooting purposes only, meters etc, and if everything in the panel is touch safe to the point that you would be unable to physically touch a line voltage terminal (with fingers or any other body part), would that classify the situation to a condition of where the employee would not be able to be exposed?
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It may possibly be considered safe from electric shock hazards, it may still present arc flash hazards.
 
zbang said:
Since you can pull the battery disconnect? Most UPSs have them, well, pretty much every one I've ever touched does- might be a connector behind a panel, might be pulling the packaged battery trays out, might be a huge DC switch on the wall behind the UPS, etc.
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You can disconnect a battery, but you can't turn it off. Take your car battery, for example. Disconnect the wires, and you still have two terminals, + and -. Drop something metal across them, and there'll be a big blue spark. Connect a bunch in series and drop something metal across them, and you'll get a bigger blue spark. Some of UPS battery plants can deliver 9,000A or more to a short circuit.
 
wtucker said:
You can disconnect a battery, but you can't turn it off. Take your car battery, for example. Disconnect the wires, and you still have two terminals, + and -. Drop something metal across them, and there'll be a big blue spark. Connect a bunch in series and drop something metal across them, and you'll get a bigger blue spark. Some of UPS battery plants can deliver 9,000A or more to a short circuit.
Click to expand...
Which means your arc flash hazard is possibly a higher concern then the shock hazard in some of those examples.
 
wtucker said:
You can disconnect a battery, but you can't turn it off.
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Are you working on the battery string or on the UPS? The OP asked about the UPS, and in almost all cases, you can disconnect the batteries from the UPS. If it's a packaged unit, like a Symetra, even the removable battery pack terminals are shrouded.

I can't think of an UPS system than can't be completely de-energized with the exception of the battery string(s) themselves (and you can always remove a link in the string or lift a lead off the terminal).

Be sensible about it.
 
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