That’s where I got my motivation to install this 3000 watt Victron system. He made it look so easy. I planned my system after his, I drew it up 2 years ago when he had the first inverter, the yellow one, but i wasn’t ready yet. Once the new Victron multi plus came out I decided to dive in, also the last prime days had a big sale on the components. Battle Born was honoring the prime day prices Plus the inverter was on sale.
New multi plus II install but main redpower wires getting too hot.
- Thread starter therabbit
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I ordered a DC amp clamp, as well as a 350A and 400A T-fuse and holder and a new switch. How can I use this DC max current number I get with the chart to determine if there is an issue? I don’t quite understand the chart, perhaps the numbers I get with the clamp meter will help. I’ve been sidelined with some other issues, but hopefully will put on the new parts this weekend and resolve this issue.
Samsonite801
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Assuming you're referring to the NEC Ampacity Chart.. Well, just break down the chart into the row and column which are significant. Look at the labeling on your cable(s) in which the fuse is in scope to protect, it should be labeled with a max temperature rating, take that over to the spreadsheet, look at the column groups, aluminum or copper, match to your conductor type (left side or right side column group), then further match column to your max temperature rating. Match that to the 4/0 Row and find applicable number.
The amp clamp will give you some idea about what current is actually going through your wire at different load levels. Fuse should be sized at 80% of the max amps the cable can safely hold (according to NEC). Apply correction factor as necessary (depending on local ambient temperature, if different than 86° F).
More info:
A temp probe can be useful as well to help see and compare actual temperatures seen in the circuit, as another tool to use along with your amp-clamp.
Good luck on your project!
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Thanks, that’s kind of what I was doing, but my temperature on the 4/0 is -50 C to +105 C. = 221F isn’t on the scale, it goes up to 194F so I wasn’t sure if I was doing it right. I’m all copper so it’s on the left side of the chart, I’m guessing use the 194F box because that’s as high as the chart goes. For 4/0 I get a number of 260, is that the maximum amount of amps that 4/0 wire should flow at on a 86%F day?
I ordered the fluke 324, it showed up and it doesn’t do DC threw the clamp, I missed the fine print, big print says AC/DC clamp meter.
now I’m trying to decide on the Fluke 325 or a Kl4in CL800 or CL900.
I ordered the fluke 324, it showed up and it doesn’t do DC threw the clamp, I missed the fine print, big print says AC/DC clamp meter.
now I’m trying to decide on the Fluke 325 or a Kl4in CL800 or CL900.
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Samsonite801
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According to Temco, that cable can do 440a..
(See specs tab too)
https://temcoindustrial.com/temco-wc0309-welding-cable-4-0-awg-25-ft-black/
Of course ambient room temp can affect operating temperature at a given current level, so providing the running cable insulation temperature stays under 221° F then it's safe. Ambient temp might be more of a thing when running closer to limits...
You just want the fuse to blow before the cable temp can reach limits.
And it's not about how many amps it can flow on an 86° F day. A short circuit can easily over-current any wire, we care about what temperature the cable is allowed to get up to before the fuse will blow. And your operating current maximum stays under the fuse-blow limit so you don't have nuisance trips. And of course the fuse size needs to be able to hold during max surge limits too.
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