I have a 50AMP breaker with 6/2 Romex wire (3ft run) connected to the Tesla Wall Connector and commissioned it to 50AMP breaker mode. I verified this by seeing 40AMP charging on the Model Y side. I took the breaker panel cover off and measured the temperature of the breaker with an infrared thermometer gun. The body where the lever is reads about 140F, the terminals for the Romex reads about 129F and the location near the busbar read up to 200F at one point. This is about 1 hour after charging started and the ambient temp is around 70F.
From my research 167F (75C) is typically the limit but I wonder how the breaker is surviving 200F without tripping or melting. These readings are measured after I've cleaned the contacts with electrical contact spray and retighten the lugs. I guess there's something seriously wrong with the breaker or it's 'within spec' on the busbar side? These are Square D QO breakers.
From my research 167F (75C) is typically the limit but I wonder how the breaker is surviving 200F without tripping or melting. These readings are measured after I've cleaned the contacts with electrical contact spray and retighten the lugs. I guess there's something seriously wrong with the breaker or it's 'within spec' on the busbar side? These are Square D QO breakers.