# Honeywell Digital Fan Coil - 16 Gauge vs. 14 Gauge



## Tonysoprano (Dec 3, 2020)

Hello!

My Question: Should 16 gauge wire be used for my Fan Coil thermostat or 14 gauge wire? The fan relay draws 6.0A which calls for 16 gauge wire. The safety fuse is tripped at 15A which calls for 14 gauge wire. 

References: The below pdf link shows the Installation Instructions for my thermostat. 
http://www.kele.com/Catalog/22%20Thermostats_Controllers/PDFs/SuitePro%20Installation%20Instructions.pdf
The attached picture, Safety Fuse Amps.jpg, below shows 15A specification.
The attached picture, Fan Relay Amps.jpg, below shows 6.0A specification for 120 Vac which is what I have.
The attached picture, Wire Dia.jpg, below shows the 16 gauge wire which has a diameter greater than 1mm but smaller than 2mm.

Background: My super installed three of these thermostats to control our Fan Coils in various rooms. So far we have had no issues. Recently, a Fan Coil tech came in to replace the motor and told me that the wires that is being used are too small in diameter and therefore dangerous. 

My Question: Should 16 gauge wire be used for my thermostat or 14 gauge wire? I understand if there is no power surge, there won't be any issues. If there is a power surge, would the 16 gauge wire burn before the fuse is tripped? Even if fuses are supposed to trip at 70% of their capacity, the surge may still first burn the 16 gauge wire before the fuse is tripped, wouldn't it?

Thank you for your time and feedback,
Tony


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## oscer1 (Jan 27, 2010)

i would of gone with the 14 gauge wire. better to have bigger wire than too small.


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## Tonysoprano (Dec 3, 2020)

oscer1 said:


> i would of gone with the 14 gauge wire. better to have bigger wire than too small.


Thanks Mike for your feedback. I couldn't agree more. The work was done 4-5 years ago. So far so good. But, I keep wondering if one day it would set my home on fire.


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## oscer1 (Jan 27, 2010)

It should be fine. Wires are probably not that long. Shorter the wire the more amps can carry.


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## SpywareDr (Jun 15, 2013)

FWIW, I agree. 14-gauge copper wire is good for up to 15 amps.



Low-voltage lighting and lamp cords10 amps18-gaugeExtension cords (light-duty)13 amps16-gaugeLight fixtures, lamps, lighting circuits15 amps14-gaugeKitchen, bathroom, and outdoor receptacles (outlets); 120-volt air conditioners20 amps12-gaugeElectric clothes dryers, 240-volt window air conditioners, electric water heaters30 amps10-gaugeCooktops and ranges40-50 amps6-gaugeElectric furnaces, large electric heaters60 amps4-gauge
Source: How to Choose the Right-Sized Electrical Wire


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## Tonysoprano (Dec 3, 2020)

oscer1 said:


> It should be fine. Wires are probably not that long. Shorter the wire the more amps can carry.


Thank you Mike. The wire length is 2-3 feet long, approximately.


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## oscer1 (Jan 27, 2010)

Your welcome


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## Tonysoprano (Dec 3, 2020)

SpywareDr said:


> FWIW, I agree. 14-gauge copper wire is good for up to 15 amps.
> 
> 
> 
> ...


This is helpful. I wonder if 15 amps is pushed through 16-gauge, will it melt the outer insulation? So are the above recommended currents or max amps it can handle? Thanks.


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## SpywareDr (Jun 15, 2013)

Tonysoprano said:


> I wonder if 15 amps is pushed through 16-gauge, will it melt the outer insulation?


Yes, trying to pull 15 amps through 16-gauge wire can potentially start a fire.




Tonysoprano said:


> So are the above recommended currents or max amps it can handle?


The above table shows the maximum amps each gauge can safely handle.


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