Print Page - Hot MNEDC breaker running close to rating

Title: Hot MNEDC breaker running close to rating - normal?
Post by: agt on July 18, 2024, 03:31:06 PM

I have an MNDC125 enclosure containing an MNEDC 80A breaker which feeds a 24V inverter. Cabling inside enclosure is 2/0, then 2 AWG to the inverter.

This setup has been working fine at 30A for a year or more.

I've recently begun placing higher 70A (~1700W) loads, and notice within a few minutes the 80A breaker is hot to the touch (160F).

Is this expected behavior running so close to the breaker's limit?

I've double-checked that the nuts are all torqued as specified (30 in-lb), and neither the lugs nor the cables seem particularly warm themselves.

Thanks
Adam

Title: Re: Hot MNEDC breaker running close to rating - normal?
Post by: FNG on July 19, 2024, 10:27:16 AM

What are you running for an inverter? I have seen recirculating currents / Ripple cause this on smaller breakers. The MNEDC1-100A breakers really may be to small for larger inverters you may want to consider the 125 or even 175A breaker depending on the inverter.

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Disconnect Boxes and Breakers => E Panel's, Disconnect Boxes and Breakers => Topic started by: agt on July 18, 2024, 03:31:06 PM