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BFL13's avatar
BFL13
Explorer II
Jun 19, 2015

Solar --Wire and Battery Fuse Size Confusion- How Big?

Can somebody please explain the math on this? I get really confused. Previously, I have seen how you have to allow 1.25 oversizing for the wires from the panel, the controller, and the wires from ...
time2roll's avatar
time2roll
Nomad
Jun 19, 2015
BFL13 wrote:
-The operating at 80% NEC guide/rule is for "continuous" (yes?) but the 1.25 over STC idea is for "occasional" times when the panel is doing more than its Voc /Isc at STC. So why can't the fuse etc be at just 1.25 too, not 1.56, since it is not expected to be running at 1.25 continually?
Continuous is defined as 3+ hours.

There is no 1.56%, only 1.25%.

For example a 40 amp continuous device needs to be on a 50 amp supply circuit including #6 wire and 50 amp breaker.
End of story.

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