Warm fuse in panel

[fletcher]

I am not an electrician. I am a home inspector who was an electrical apprentice for 2 years.....10 years ago!

Anyway, I found a warm 20 amp fuse in a panel. The temp of the fuse was 101 to 104 depending on how close I held the laser. The fuse was for the washing machine which was running.

The fuse next to it was 76 degrees which was room temp. I don't know what was on that circuit.

The buyer of the home has a relative who is an electrician and they are going to put in a new breaker panel. However, was I correct in calling out the warm fuse ? I have been feeling fuses for 10 years and this was the first warm one I found. What are the causes?

I did not pull the cover, to see what was going on. I told her to call her electrician relative for further evaluation.

 

[jbelectric777]

We dont go by measuring the temperature of overcurrent devices, we use an ammeter to measure the current in amperes being drawn in the circuit. The warm is the current flowing and is not normal. Its caused by too much load on that circuit, 16 is max we wanna see for a 20. Other causes can be a lower voltage (sometimes homes are at the end of a distribution line) less voltage is higher current, a loose connection anywhere can cause excessive current. New code washer and dryer must be on a seperate 20 amp branch circuit. Existing ya cant make em do it but inform the new owners of the condition.

 

[petersonra]

I don't think that is excessively warm. Fuses generate heat by their very nature. So do typical circuit breakers.

If they are seeing a significant portion of their rated current, they should be warm to the touch.

 

[fletcher]

Thanks.

I don't carry an amp meter. sice we are not required to take those measurements. I like the laser thermometer because I can check the temps on heat registers and other items. And when people ask, "how warm was it" I can say I took it's temp and it was 104 degrees rather than 200

Thanks again, I love this site.

 

[haskindm]

We dont go by measuring the temperature of overcurrent devices, we use an ammeter to measure the current in amperes being drawn in the circuit. The warm is the current flowing and is not normal. Its caused by too much load on that circuit, 16 is max we wanna see for a 20. Other causes can be a lower voltage (sometimes homes are at the end of a distribution line) less voltage is higher current, a loose connection anywhere can cause excessive current. New code washer and dryer must be on a seperate 20 amp branch circuit. Existing ya cant make em do it but inform the new owners of the condition.

Careful about making sweeping statements such as 16 amps max on a 20-amp circuit. 16 amps is the maximum CONTINUOUS LOAD (3 hours or more) on a 20 amp circuit. A washer is certainly not a continuous load. Even if it ran for 3 hours it has cycles where the current draw would vary. Code does not require the washer to be on a separate branch circuit. It says that the laundry receptacle(s) should be on a 20 amp circuit. There can be more than one receptacle on the "laundry circuit". I agree that the warm temperature may be perfectly normal. The tightness of the connection should be checked and the amperage should be measured. Since a fuse works in response to temperature, it must not have been too warm or the fuse would have blown.