MVT Plus to AC Pro Trip Unit Settings Conversion

[bbryant]

I have several breakers I need to convert settings from MVT and MVT Plus to AC Pro. Is there a conversion chart out there on the free market? We send the settings requests to our engineering staff, but it seems like this should be accomplished at technician level in case of emergencies. Thank you in advance for your suggestions.

[AaronCBI]

My company does AC PRO trip unit retrofits quite often and I perform the final testing on them. I probably test 3 or 4 a month.
To my knowledge, there are not any conversion charts and the only way to accurately program the same tripping values into the AC PRO would be consulting the time current curves of both trip units, and trying to match the pickup and delay values to the best of your abilities.
When our end users have AC Pro trip units installed, they always consult engineering staff and reference the local distribution studies to obtain trip unit settings prior to placing it in service, and we ship the circuit breakers with all minimum trip values so they can be set by customer.

[AaronCBI]

Also, the AC Pro team are always very helpful and easy to establish a good working relationship with. I would encourage you to give them a call and see if they can help you out. They are always more than happy to help me out with any requests that I have.
Good Luck!

[bbryant]

Also, the AC Pro team are always very helpful and easy to establish a good working relationship with. I would encourage you to give them a call and see if they can help you out. They are always more than happy to help me out with any requests that I have.
Good Luck!

I plan to call them in the morning. Unfortunately, that doesn’t help me tonight. Thank you for the reply.

[SecondGen]

I plan to call them in the morning. Unfortunately, that doesn’t help me tonight. Thank you for the reply.

If you need an answer right away I would suggest comparing the Time Current Curves of the two trip units. Look up the time tolerance for each MVT setting and compare to the tables and curves in the AC Pro manual. You can find all the necessary documents online.

[Kalbi_Rob]

I have several breakers I need to convert settings from MVT and MVT Plus to AC Pro. Is there a conversion chart out there on the free market? We send the settings requests to our engineering staff, but it seems like this should be accomplished at technician level in case of emergencies. Thank you in advance for your suggestions.

I agree with SecondGen above, in a hurry, you have to match the AC Pro trip curves as close to the replaced trip unit trip curves. I disagree that this should be accomplished at the technician level since it requires a PE to determine the settings and absorb the liability and responsibility of the arc flash hazard created from the SCCS. As a technician, I don't want to be the one going to court after an incident occurs based on the settings inputted into the breaker without proper coordination, god forbid it results in injury or death.

I always remind the customer that the settings are only a close representation of the original study, and that in accordance with NFPA 70E, a revision of the Arc Flash study and SCCS need to be updated as the electrical distribution system has been altered and now violates the NFPA 70E Arc Flash Risk Assesment, which also will require engineering to determine the proper settings for the altered breakers.

NFPA 70E 130.5(G)
The incident energy analysis shall be updated when changes
occur in the electrical distribution system that could affect the
results of the analysis. The incident energy analysis shall also be
reviewed for accuracy at intervals not to exceed 5 years.

[edtappan]

I have several breakers I need to convert settings from MVT and MVT Plus to AC Pro. Is there a conversion chart out there on the free market? We send the settings requests to our engineering staff, but it seems like this should be accomplished at technician level in case of emergencies. Thank you in advance for your suggestions.

Here's an update for this thread.

Last week URC added a Settings Conversion Calculator to their site. They have a lot of trip units listed. Check their site for more details.

http://www.utilityrelay.com/SettingsConversion.html

[clipboardwarrior]

Here's an update for this thread.

Last week URC added a Settings Conversion Calculator to their site. They have a lot of trip units listed. Check their site for more details.

http://www.utilityrelay.com/SettingsConversion.html

You should all listen to this guy. He's totally boss level when it comes to all things breaker.

[Kalbi_Rob]

Here's an update for this thread.

Last week URC added a Settings Conversion Calculator to their site. They have a lot of trip units listed. Check their site for more details.

http://www.utilityrelay.com/SettingsConversion.html

I would like to point to the disclaimer on the site:
"DISCLAIMER: URC is not responsible for determining adequacy, appropriateness or results of improper settings.
The Settings Conversion Tool is intended to be used as a starting point to match existing settings. Converted settings may not exactly match existing. Final settings should be determined by a Protection Engineer or other Qualified Person. Settings affect Safety, Equipment (assets), Processes, etc. The process of determining settings requires additional information such as application-specific studies. These studies can include Short Circuit, Protection/Coordination, Arc Flash, etc. Simply converting existing settings may or be adequate or appropriate."

This is essentially saying URC takes no responsibility for the revised settings their conversion calculator provides, thus I would reference you to NFPA 70E that states a SCCS must be performed, atleast on that single breaker.

Obviously, most customers have no regards for this requirement and just want the breaker to work, but you should be wary of taking that responsibility on if a fault occurs later and your company is held liable.