Anyone else bothered by the small wires for a Watt's Up / Doc Wattson?

[Beaufort]

So they build these with 14 AWG pigtails, but rate the Amperage up to 100 A?  According to their FAQ, they don't claim this is a problem.  So in order to wire one of these into a small RE system, you have to go from your huge battery cable #6, #4, or #0 AWG down to 14 AWG?  Does anyone know if this presents any code issues (NEC)?  I've been using these for a while and they work just fine, but something about this doesn't seem quite right.

[fabricator]

They are made for use with RC cars and planes.

[TomW]

They are made for use with RC cars and planes.

Truth.

I sure did not see any UL compliance listed in the paperwork or on the unit.

Really no big deal with the short run of the pigtails. Just use proper terminal blocks to connect them and  I doubt you will have troubles but the rest of my system would be in meldown if I had to handle that kind of charging for any time. I have seen 70+ amps from the turbine with no signs of heat problems but short term intermittent charging.

I just would not use it on the inverter at all  myself.

The wire insulation is high temperature silicone stuff so even at 100 amps I don't think enough heat will build up in a 2 inch hunk of #14  to scorch that or pop the wire itself.

DanB or someone he knows had one scorch the case I think but that was well beyond 100 Amps something like 150 Amps in a big blow from a turbine.

Just my opinions and, believe me, I have been very wrong a few times.

Tom

[BrianSmith]

If you had 100A running thru 14 AWG for say 6 inches == 100*100*0.00126 = 12.6W 

It would probably burn the insulation off that in a minute or two.  Depends how long the wire is and how long you run it at that current. 

I'm thinking that's not a steady state rating, probably a peak current rating.

[Beaufort]

The wire insulation is high temperature silicone stuff so even at 100 amps I don't think enough heat will build up in a 2 inch hunk of #14  to scorch that or pop the wire itself.

Agreed, I came to the same conclusion and I'm sure they couldn't put thicker wire into an SMD board like that without a major change to the form factor.  Still, I like to build stuff that any inspector or electrician can look at it without that wincing, angry look just before they ask if I really know what I'm doing.  So having thick stuff coming to a power panel that ties into teeny little things like these meters is a dead tip-off.  So I think we can agree that these will safely work, but does this violate any portion of NEC regarding conductor ampacity? 

Maybe I should just go buy a copy of NEC....questions like this come up all the time.

[BrianSmith]

Wikipedia has a table on AWG resistance and current rating.  I'm sure there is a NEC document for this as well that the building inspector would reference.

This table says 20 / 25 Amps rating for AWG 14 based on the plastic insulator type.


AWG    Diameter    Turns of wire    Area    Copper
resistance[6]    NEC copper wire
ampacity with 60/75/
90°C insulation (A)[7]    Approximate
stranded metric
equivalents
(inch)    (mm)    (per inch)    (per cm)    (kcmil)    (mm²)    (Ω/km)    (Ω/kFT)
0000 (4/0)    0.4600    11.684    2.17    0.856    212    107    0.1608    0.04901    195 / 230 / 260    
000 (3/0)    0.4096    10.404    2.44    0.961    168    85.0    0.2028    0.06180    165 / 200 / 225    
00 (2/0)    0.3648    9.266    2.74    1.08    133    67.4    0.2557    0.07793    145 / 175 / 195    
0 (1/0)    0.3249    8.252    3.08    1.21    106    53.5    0.3224    0.09827    125 / 150 / 170    
1    0.2893    7.348    3.46    1.36    83.7    42.4    0.4066    0.1239    110 / 130 / 150    
2    0.2576    6.544    3.88    1.53    66.4    33.6    0.5127    0.1563    95 / 115 / 130    
3    0.2294    5.827    4.36    1.72    52.6    26.7    0.6465    0.1970    85 / 100 / 110    196/0.4
4    0.2043    5.189    4.89    1.93    41.7    21.2    0.8152    0.2485    70 / 85 / 95    
5    0.1819    4.621    5.50    2.16    33.1    16.8    1.028    0.3133       126/0.4
6    0.1620    4.115    6.17    2.43    26.3    13.3    1.296    0.3951    55 / 65 / 75    
7    0.1443    3.665    6.93    2.73    20.8    10.5    1.634    0.4982       80/0.4
8    0.1285    3.264    7.78    3.06    16.5    8.37    2.061    0.6282    40 / 50 / 55    
9    0.1144    2.906    8.74    3.44    13.1    6.63    2.599    0.7921       84/0.3
10    0.1019    2.588    9.81    3.86    10.4    5.26    3.277    0.9989    30 / 35 / 40
11    0.0907    2.305    11.0    4.34    8.23    4.17    4.132    1.260       56/0.3
12    0.0808    2.053    12.4    4.87    6.53    3.31    5.211    1.588    25 / 25 / 30 (20)    
13    0.0720    1.828    13.9    5.47    5.18    2.62    6.571    2.003       50/0.25
14    0.0641    1.628    15.6    6.14    4.11    2.08    8.286    2.525    20 / 20 / 25 (15)    
15    0.0571    1.450    17.5    6.90    3.26    1.65    10.45    3.184       30/0.25
16    0.0508    1.291    19.7    7.75    2.58    1.31    13.17    4.016    â€” / — / 18 (10)

[zap]

So they build these with 14 AWG pigtails, but rate the Amperage up to 100 A?  According to their FAQ, they don't claim this is a problem.

Both are rated for 50 amp continuous.

[defed]

i believe that my turnigy meter has 12 awg wires.  so far it is working good.