Cable size & Fuse/Circuit Breaker for 2000W inverter?

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  #1  
Old 03-17-19, 04:58 AM
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Cable size & Fuse/Circuit Breaker for 2000W inverter?

Hi dear DoItYourself.com community,

I would really appreciate some help with the following (it's not that I'm some skimpy freeloader; I'm simply growing tired of conflicting answers of professionals - auto electricians, electronics supply stores etc. - from around here):

I have a 2000W inverter (constant output; peak up to 4000W) hooked onto a 12V auxiliary car battery. Well, not yet, but I'd like to soon.
The supplied cable with the inverter is roughly 0.5m long and 10 AWG / 600V / 105C / 16mm2 - mind you, that's what it says on the cable. According to 'RapidTables.com' [*1] states that 10AWG cable is actually 5.26mm2 or 2.59mm ... so, yeah, weird! The gauge stated on the cable - 16mm2 - rather corresponds to AWG5 of 4.62mm, no?

I will only be running minor appliances up to 700W (a hand / stick-blender), but the next owner of the campervan might choose to run a micowave 1000W+ or simultaneous appliances on it. I just wanna be on the safe side. The fuse, obviously, is for near the 2nd/auxiliary battery and on the cable to the inverter.

The distance from the 2nd/auxiliary battery will be approximately / maximally 0.5m in length. I typed in "0.5m" and "166 Amps" (2000W/12V) at EnergyMatters.com.au [*2] and they recommend a minimum wire size of 24.3mm2 (i.e. ~AWG3; 5.83mm) and, further, the following Maximum Fuse Size Recommendation

Cable Size
Max Fuse / Breaker Size
6mm - 25amps
16mm - 70amps
25mm - 90amps
32mm - 110amps
50mm - 150amps

So I if I went with the minimum AWG3 gauge & the recommended 25 Amps fuse / breaker, I will run the risk of it blowing every time the inverter draws as little as 300W (25 Amps x 12V), right?

Any comments on this? Many many thanks in advance.

Sandro aka SwissBliss77

----------------------------------------------------------
References / resources:
*1: https://www.rapidtables.com/calc/wir...uge-chart.html
*2: DC cable sizing calculator - Energy Matters
 
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  #2  
Old 03-17-19, 08:17 AM
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The 12 volt amps is approximately 10x the 120 volts.

1000 watt microwave draws about 8.3 amps. That means you need at least 83 amp on the 12 volt side. 100 amp fuse and cable would be recommended.
 
  #3  
Old 03-17-19, 08:36 AM
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Hi, if the mfg. supplied the cable for that inverter why would you want anything larger?
What am I missing?
Geo
 
  #4  
Old 03-17-19, 10:41 AM
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Post the make and model of your inverter so we can look up the specs.
 
  #5  
Old 03-17-19, 12:29 PM
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Yes..... the make and model would be very helpful.

There is not only running wattage to consider but startup wattage.
I'd be connecting that inverter on a short run to a 12v battery with at least #1 copper and a 200A fuse.
 
  #6  
Old 03-18-19, 03:56 AM
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Dear Community,

Thank you heartily for all your swift replies.
@Geochurchi: What you are - presumably - missing? Well, that (1) the given specs on the supplied wire gauge seem to be off / conflicting & (2) that the cable is too thin a gauge for a 2000W inverter hooked onto 12V battery.

@all / @joed, @PJmax
Please don't forget that mains voltage in Australia is 230V 50Hz. Forgot to emphasize or even mention that, sorry.

It's a GIANTZ 2000W/4000W Pure Sine Wave Power Inverter 12V-240V w/Remote
https://www.catch.com.au/product/gia...waAiWAEALw_wcB

Once again, many many thanks for all your swift help.

Best regards,
Sandro
 
  #7  
Old 03-18-19, 04:26 AM
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Please don't forget that mains voltage in Australia is 230V 50Hz. Forgot to emphasize or even mention that, sorry.
Most of the people here are from North America. That was an important fact I should have picked up when you used metric wire sizes.

That would have no effect on the values I gave for the battery supply. The only difference is the AC output current would half. 1000 watts is still 1000 watts and the 12 volt supply needs to be setup for 83 amps.
 
  #8  
Old 03-18-19, 05:18 AM
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Hi, if you could contact the mfg. ask them the question, seem difficult to find there contact info.
Geo
 
  #9  
Old Yesterday, 04:02 AM
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@Geochurchi - I don't think that's gonna happen. Certainly some Chinese contractor who manufactured this. :-/
 
  #10  
Old Yesterday, 04:06 AM
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Most of the people here are from North America. That was an important fact I should have picked up when you used metric wire sizes.

That would have no effect on the values I gave for the battery supply. The only difference is the AC output current would half. 1000 watts is still 1000 watts and the 12 volt supply needs to be setup for 83 amps.
@Joed
Yeah, I hear ya - I kinda used AWG & metric systems rather haphazardly. That uncanny blend is what we get over here when importing stuff from China (etc.) which also exports to the US & CAN.

Don't I have to use the max output 2000W to calculate the fuse/breaker & the cable gauge?
Just in case someone once uses a microwave simultaneously with another appliance.

What
- breaker (Amps)
- cable gauge (mm / mm2)
would you use for a approximately 0.5m long cable from the aux battery --> inverter?

Many many thanks
Sandro
 
  #11  
Old Yesterday, 05:19 AM
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Don't I have to use the max output 2000W to calculate the fuse/breaker & the cable gauge?
Just in case someone once uses a microwave simultaneously with another appliance.
You probably should. That would double all the values in my calcs.
 
  #12  
Old Yesterday, 06:19 AM
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Hi, this link you have the answer to your cable concerns.
https://invertersrus.com/battery-cables/
Geo
 
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