Con fused

[belfert]

I use ATC fuse blocks for all DC stuff since that is what the bus wiring uses.  I probably have at least a dozen of each size.  Delcity used to require minimum orders and I would add cheap ATC fuses to my order to meet the minimum.

[Iceni John]

Normal practice is to never fuse the ground connection.  If you do, consider using an auto-reset breaker.  With that said, there is nothing inherently wrong with fusing the ground connection of a battery aside from introducing a failure point, presuming you fuse the positive side coming out of the battery.

Some years ago when Sean Welsh was contributing to this forum he advocated using catastrophe fuses on the negative side of house battery banks.   On his cogent advice (and he certainly knows more about such matters than me!) I've done the same  -  I have a quick-blow 300-amp Class T fuse on the negative of each battery bank's house output.   For individual load protection I'll still also use fuses or breakers on the positive of each DC house circuit.

John

[bevans6]

While catastrophe fuses in the grounds of a house back make sense if it's just a house bank, if you set up to bridge to boost start batteries they could be a problem with starting current loads.  Just to be aware if you do that.

[Iceni John]

While catastrophe fuses in the grounds of a house back make sense if it's just a house bank, if you set up to bridge to boost start batteries they could be a problem with starting current loads.  Just to be aware if you do that.

I've taken care of that possibility by having two Blue Sea 9001 switches for the starter boost connection, one for positive and the other for negative.   This way if I'm boosting the start batteries the negative is also connected directly to the starter, bypassing the expensive ($45 each!) Class T fuses.   I don't know exactly what the current draw is to start my engine, but I assume it's briefly more than the fuses' 600 combined amps.

John

[bevans6]

The fuses are in series with the battery, you don't add amps in series circuits.  If you have two 300 amp fuses in series, you have a 300 amp fuse.  If fuses are in parallel, they share the current between them.

Brian

[Iceni John]

The fuses are in series with the battery, you don't add amps in series circuits.  If you have two 300 amp fuses in series, you have a 300 amp fuse.  If fuses are in parallel, they share the current between them.

Brian

Two independent battery banks, each with its own 300A catastrophe fuse, both banks available to boost the starter if needed (or just one bank or the other if I choose).

John

[bevans6]

That makes sense!