Published: 3 February 2014
Category: Q&A
Colin asks this question about re-setting an ABB SACE PR111/P air circuit breaker (ACB), and whether this could cause tripping. It has been answered by ABB (Theme – Distribution Equipment):
This Q & A is one of thousands posted in our Technical Expertise area, and answered on a daily basis by our Voltimum Experts.
Question: We noticed recently that a 1250A ACB by ABB, having a PR111/P release, is protecting an 800A switchboard.
The PR111/P is set at 1250A and we would like to set it down to 800A.
The normal load is about 350A, with occasional starting surges to 600A.
Is there any likelihood that the unit will trip when the setting is changed?
Answer: This breaker should not trip as you adjust the settings since the overload tripping times are in minutes.
Therefore, even if you go through a lower setting than the current flowing in the breaker whilst getting to your required setting, there is little likelihood that this low setting will remain in place for the length of time required to trip the breaker.
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