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DC fuse polarity?

coffeej

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Jan 2, 2023
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Virginia
I'm installing a DC breaker/fuse (Nader NDB1-125) between a set of two EG4 Lifepower batteries and an all-in-one inverter (6500-EX EG4). I'm confused about which is considered "line" and which is "load."

I get the sense from others' pictures that the batteries should be considered line. Is that true?

Also, is it okay if I mount the fuse upside down?
 
I've never seen a polarized fuse. Please share a picture and some details.

Battery should be line side, yes.

Upside down should be fine, but on the same vane, polarized fuses shouldn't be possible. So, I'll not make any recommendations there.

Edit: nevermind it's a breaker, somehow I overlooked the part number. Upside down is fine.
 
These breakers are for AC and DC.
I'm not sure why "Line" and "Load". For switches having exposed blades, this ensures not readily accessible hot contacts. But I don't see the purpose for breakers.
I don't see any indication they are polarized, only meet spec for one polarity of DC connection.

Their rated breaking current 10,000A is not particularly high. You may be relying on EG4 Lifepower to handle severe shorts.
There has been some discussion on this topic. We'd rather use class T fuse with 20k AIC, or some breakers that are 50k AIC. But people have tested shorts and seen BMS successfully interrupt them.


 
I'm installing a DC breaker/fuse (Nader NDB1-125) between a set of two EG4 Lifepower batteries and an all-in-one inverter (6500-EX EG4). I'm confused about which is considered "line" and which is "load."
Some DC breakers are polarized, like yours.

With directional DC breakers, the highest potential of energy goes to the input side (marked with a + or "LINE").

If installed the wrong way, bad things can happen (ETL testing).

Here's a YouTube DC breaker tutorial from MidNite Solar.
 
Some DC breakers are polarized, like yours.

What makes you think his are polarized?
I don't find that in documentation, or labeling.

Have any links supporting this use of "LINE"?

With directional DC breakers, the highest potential of energy goes to the input side (marked with a + or "LINE").
 
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