Shouldn’t fuses be sized to protect the cables David? Don’t understand why it would overload, if one fuse blew surely they would both go as soon as you tried to draw more than the cable rating?The cable from battery to inverter should be protected by a fuse.
This means if you have TWO cables, you need to fuses.
This also means that if one fuse blows/fails, you will unknowingly be pulling all the current throught the one remaining intact circuit which could overload THAT cable until it's fuse blows.
the Ampacity of 2 X 25mm2 cables is the same as 1 X 50mm2 cable, but the real world application of using two is not as good.
That's very true and also unless you are certain the cables are from the same batch then there may be some differences in cable manufacture which may cause greater resistance in one cable than the other which may in turn lead to further problems when using two cablethe Ampacity of 2 X 25mm2 cables is the same as 1 X 50mm2 cable, but the real world application of using two is not as good.
indeed, the fuse should be lower than the cable rating. So instead of having say a 400A fuse on a 95mm2 cable, you might have a 200A fuse on each of the 50mm2 cables. (I am just plucking a number out the air here).Shouldn’t fuses be sized to protect the cables David?
If only one fuse failed (not all fuses are created equally in terms of quality and the variance against the claimed rating can be dramatic - both higher AND lower) and maybe if there was a load close to the total rated load, you could have just one fuse fail as it is a poor fuse, or the other fuse still be intact as it is a poor fuse in the opposite direction.Don’t understand why it would overload, if one fuse blew surely they would both go as soon as you tried to draw more than the cable rating?
But you could join the cables at both ends through one fuse, then it becomes a h duty cable, silly mind you unless space or bending around tight corners.indeed, the fuse should be lower than the cable rating. So instead of having say a 400A fuse on a 95mm2 cable, you might have a 200A fuse on each of the 50mm2 cables. (I am just plucking a number out the air here).
If only one fuse failed (not all fuses are created equally in terms of quality and the variance against the claimed rating can be dramatic - both higher AND lower) and maybe if there was a load close to the total rated load, you could have just one fuse fail as it is a poor fuse, or the other fuse still be intact as it is a poor fuse in the opposite direction.
Then the next time the inverter is used, all the current is going down just one of the two cables.
So two things occur now in fact ...
1) you are running all the load down that cable so even if you are not running the inverter to its rated capacity, you could be always close to the that single cables capacity. makes it run hot and heat = power loss = inefficiency
2) with all the load on the single cable, your voltage drop will be a lot greater than with both cables in play - again creating inefficiencies.
that is an option and I have often cut an extra opening on a megafuse cover to accommodate a second cableBut you could join the cables at both ends through one fuse, then it becomes a h duty cable, silly mind you unless space or bending around tight corners.