No, that’s why I run all 20/0 wire.
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4/0 cable: Pushing Over the Current Limit
- Thread starter EPicTony
- Start date
I believe so but I could have confused what Amps I was at. I'll double check next sunny day and post back.
I run 2/0 inverter to bus bar (3 inverters) then 4/0 to the battery racks (7 batts x 2)
wpns
Solar Joules are catch and release
Yeah, don’t forget the ends are likely to be warmer.
TM48
Solar Wizard
Keep in mind with 3 6000xps you'll be be running them at absolute max charger capability of 140 amps each. I wouldn't do it.
Probably go with 110A each for a total of 330A. How does that sound ?
TM48
Solar Wizard
I had mine set at 110 for awhile. That's reasonable. Mine are set to 90 each right now but I don't have as much battery as you do.
Vigo
Solar Wizard
I personally am not comfortable running anything much past 140f unless im REALLY unlikely to touch it. No way in hell do i want a 100c anything anywhere where i can touch it, at least as a design choice...
Which is funny.. because im an auto tech and there are nuuuuumerous spaces way over that on a running or recently running engine bay, and i work around that just fine. But other than getting my hand sucked into a running belt drive or bounced off a spinning fan, burns are the ONLY concern im really worried about there. It's kind of like how i explain shock danger to my students: A housecat is not that dangerous, but it might be if you are already on a ladder. I dont want to experience any reflexive jerking movements in an environment where something ELSE is even more dangerous. I can touch 140f+ without 'jerking' away from it, but 100c probably not! And then bam, jam the other end of the same arm into some 200-400v something or other terminals and make it worse? Yeah, should try and protect those from incidental contact too etc etc but if im in 'reflex mode' there's not much that is totally stupid proof..
Maybe im paranoid but that's how i think about safety. I dont want anything painful enough to induce reflexive movement into something even more painful.
Which is funny.. because im an auto tech and there are nuuuuumerous spaces way over that on a running or recently running engine bay, and i work around that just fine. But other than getting my hand sucked into a running belt drive or bounced off a spinning fan, burns are the ONLY concern im really worried about there. It's kind of like how i explain shock danger to my students: A housecat is not that dangerous, but it might be if you are already on a ladder. I dont want to experience any reflexive jerking movements in an environment where something ELSE is even more dangerous. I can touch 140f+ without 'jerking' away from it, but 100c probably not! And then bam, jam the other end of the same arm into some 200-400v something or other terminals and make it worse? Yeah, should try and protect those from incidental contact too etc etc but if im in 'reflex mode' there's not much that is totally stupid proof..
Maybe im paranoid but that's how i think about safety. I dont want anything painful enough to induce reflexive movement into something even more painful.
OzSolar
Whatever you did, that's what you planned.
No need to wait for a heat gun to tell you where/if there's a problem. Just need to check the Voltage drop.
To me the easy math and super quick test is V x A = Watts = Heat
Also in my experience it's not the wire that's going to get you, it's the connections and usually it's the breakers. Also, from what I've seen breakers have more resistance than an equivalent fuse.
I carefully run every new system up to it's full rating while checking voltage drop across the entire system as well as every terminal, fuse and breaker.
EG: 1V drop across the entire 48v system @ 420 amps = 420 watts of heat.
Most important is finding what is responsible for that 1V. EG: 50% of it one connection or it's evenly spread out across the whole system?
Try it sometime, it's very informative.
Exactly, please check insulation temp rating everyone.That's for 105°C rated UL 1426/Marine wire.
Please confirm your insulation rating before you go crazy with things...
Many here would be incredibly surprised at how much current these cables can actually handle.
I don't want to come off as a bad example but I've been able to push a ridiculous amount of current through small conductors
200c rating silicone wire is supreme.
Something else to mention is even if your conductor and insulation and lug can handle the temperature, the terminal you are connecting to might not. Especially if it's a breaker.
These devices have temperature ratings and you cannot ignore them! Just because your wire can handle it doesn't mean everything else can.
These devices have temperature ratings and you cannot ignore them! Just because your wire can handle it doesn't mean everything else can.
I just imagined a cascading event of you touching one thing hot, jerking back "OW" and smacking something live, sparks fly "YOW!!" Ricochet off that and bounce off the hot thing back to the high voltage and more sparks and sizzles back and forth cartoon styleI personally am not comfortable running anything much past 140f unless im REALLY unlikely to touch it. No way in hell do i want a 100c anything anywhere where i can touch it, at least as a design choice...
Which is funny.. because im an auto tech and there are nuuuuumerous spaces way over that on a running or recently running engine bay, and i work around that just fine. But other than getting my hand sucked into a running belt drive or bounced off a spinning fan, burns are the ONLY concern im really worried about there. It's kind of like how i explain shock danger to my students: A housecat is not that dangerous, but it might be if you are already on a ladder. I dont want to experience any reflexive jerking movements in an environment where something ELSE is even more dangerous. I can touch 140f+ without 'jerking' away from it, but 100c probably not! And then bam, jam the other end of the same arm into some 200-400v something or other terminals and make it worse? Yeah, should try and protect those from incidental contact too etc etc but if im in 'reflex mode' there's not much that is totally stupid proof..
Maybe im paranoid but that's how i think about safety. I dont want anything painful enough to induce reflexive movement into something even more painful.
Excellent advise. Now I just need to wait for a sunny day to test it. Cloud city in NE Ohio today.
Vigo
Solar Wizard
Exactly! Murphy's Law dictates my dumb ass will suffer the most outrageous perfect storm of bullshit, so i try to keep that in mind when thinking of 'small' dangers.. they could lead to bigger ones!
Just to show what the expected voltage drop would be for the OP's cabling.
I was working to fix similar issue by using 2nd pair of 4/0 cables and a 2nd 250A breaker. The key to doing that is being able to get a mechanical interlock between the two breakers so that if one trips they both trip. The two 250A breakers were much cheaper then upgrading to a much larger breaker and subsequent larger cables.
robbob2112
Doing more research, mosty harmless
How did you solve it? a bar across all 4 handles? a 4 pole breaker? something else?
I'm using Noark breakers for main battery disconnect and they have a interlock for them: https://products.na.noark-electric.com/products/MIT22NA
Bluedog225
Solar Wizard
I will only do this in the crappy seasons for solar in NE Ohio (Dec Jan Feb) to capitalize when the sun pops out for a short time. In the other months I keep the charge current about 230A (for 14 batteries). On the plus side the 157W in winter helps with heating a little.
DPC
Canada, Great already
Going to be HOT!!!!Checked it: 600V, 105degC welding cable. Happy I don't have to spend more $$$ this solar is getting expensive
300mcm 90c 400 amps free air ( times three on a 1200 amp breaker )
But it’s hot
At full load your not going to touch one of those phases feeding the main
You will burn your hand
I never ran super flex at temperatures higher than I would 90c pvc or nylon just because that so much heat it’s bad fur everything around it
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SomethingAppropriate
Cannibalism starts with a kiss.
But pay attention to the lugs and bends.Sunshine_eggo said it's only 157w over 20ft., doesn't seem too bad for a few hrs when we have full sun. Not going to grill any hotdogs with it
Yes, going to test the voltage drop / heat when I get sun and full current. Thanks for all the good ideas everyone !
DPC
Canada, Great already
Heat has to go someplace...Sunshine_eggo said it's only 157w over 20ft., doesn't seem too bad for a few hrs when we have full sun. Not going to grill any hotdogs with it
9 watt LED.
Put it in a closed or semi closed light fixture and it could set you house on fire, but its only 9 watts...
Old fixture may have been rated for 100 watts of incandescent but they never caught fire.
Its what else might be cooked with the device in that localized heat you need to consider
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