Personal safety grounds

[101010]

What is your procedure for personnel safety ground while working on a transformer after you test to make sure transformer is denergized ? 480 v to 208 v trans. Does connecting the proper size ground wire connected to the grounding system and a across the 3 phases suffice. I know you connect to the ground first then to the phases and disconnect in the opposite order. any other suggestions?

 

[xformer]

What is your procedure for personnel safety ground while working on a transformer after you test to make sure transformer is denergized ? 480 v to 208 v trans. Does connecting the proper size ground wire connected to the grounding system and a across the 3 phases suffice. I know you connect to the ground first then to the phases and disconnect in the opposite order. any other suggestions?

I would verify voltage reading on line side of transformer, then proceed with connection. I have used a special 4/0 grounding conductor to connect all 3 phases to each other then to ground upstream from where I am working...

 

[iwire]

I am dead set against making a short circuit in 600 volts and below.

I lock out tag out and go to work.

OSHA is fine with that.

 

[xformer]

I am dead set against making a short circuit in 600 volts and below.

I lock out tag out and go to work.

OSHA is fine with that.

That would be the very first thing that I did...

 

[zog]

What is your procedure for personnel safety ground while working on a transformer after you test to make sure transformer is denergized ? 480 v to 208 v trans. Does connecting the proper size ground wire connected to the grounding system and a across the 3 phases suffice. I know you connect to the ground first then to the phases and disconnect in the opposite order. any other suggestions?

"Proper size" means your groud set it tested and rated for the avialble fault current at the connection point. ASTM F 855

 

[rogertaylorlive]

This is the mandatory part and OSHA will help you more in this regard..

 

[iwire]

This is the mandatory part and OSHA will help you more in this regard..

What is mandatory?

LOTO is, grounding out is not. At least at the voltage levels I work with.

 

[don_resqcapt19]

"Proper size" means your groud set it tested and rated for the avialble fault current at the connection point. ASTM F 855

Back when I started, it was common to see things like jumper cables and log chains used for this purpose in 480 switchgear. I understand why that is not correct, but it was a common practice, at least around here.

 

[Smart $]

What is mandatory?

LOTO is, grounding out is not. At least at the voltage levels I work with.

Not OSHA required, but may be mandatory under an entities documented safe work procedure. It is an additional safety measure to mitigate residual charges, such as a system with capacitors or other load equipment with the potential to backfeed the system (wind-milling fan motors?).

 

[iwire]

Not OSHA required, but may be mandatory under an entities documented safe work procedure.

Of course, but I was responding to a post about OSHA.

It is an additional safety measure to mitigate residual charges, such as a system with capacitors or other load equipment with the potential to backfeed the system (wind-milling fan motors?).

I think it is ridiculous under 600 volts and is more likely to lead to a injury if someone leaves it in place.

 

[Smart $]

Of course, but I was responding to a post about OSHA.

I know. Just seemed like best place to post what I had to say at the time. Sorry if I inconvenienced you.

I think it is ridiculous under 600 volts and is more likely to lead to a injury if someone leaves it in place.

While I agree with the underlying reason, each situation should be analyzed independent of others, prior to performing work, with precautionary measures acted on accordingly. While I don't care to admit it, I've been shocked by a 144VDC system that made me me stop and re-evaluate.