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19 amp equipment on 30 amp overcurrent protection.

don_resqcapt19

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
kwired said:
Is there other load(s) on this circuit? A 20 amp breaker really should be able to handle 19 amps for a few hours minimum or maybe even hold indefinitely.

1 minute is way too short of trip time, unless breaker is seeing well over 20 amps.
Click to expand...
As long as the breaker temperature is not greater than 40°C it should hold 20 amps forever.
 
W

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
Ok, we've established the following:

1) The voltage at the load when operating is 124V, so no excessive voltage drop.

2) The load is very likely the only load on the breaker.

3) The load is a motor.

We don't have:

4) Measurement of the actual current draw when the breaker trips.

At this point my first guess is that there is something wrong with the load, causing it to draw overload current, perhaps on the order of 30A on the basis of breaker trip time.

My second guess is a loose connection at the breaker (causing heat which will trip the breaker) or a defective breaker.

-Jonathan
 
rambojoe

rambojoe

Senior Member
Location
phoenix az
Occupation
Wireman
Its a c.b. to a outlet (next to the panel?- 100' away?) w/a 50' 10awg extension cord to a spider box then a 12awg sow to the equipment.
Something tells me the volt reading is at the panel.
This means at best its plugged into a gfi or a protected 20a twist lock on the spider box.
Not exactly less that likely its the only load..
Thats not even getting into exactly what type of torque motor it is or the exact setup...
 
W

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
rambojoe said:
Its a c.b. to a outlet (next to the panel?- 100' away?) w/a 50' 10awg extension cord to a spider box then a 12awg sow to the equipment.
Something tells me the volt reading is at the panel.
This means at best its plugged into a gfi or a protected 20a twist lock on the spider box.
Not exactly less that likely its the only load..
Thats not even getting into exactly what type of torque motor it is or the exact setup...
Click to expand...

Ok, I admit I was making guesses based on the OP's description.

In post #21 they are asked if they measured the voltage at the end of the extension cord, and they answered 124V.

In post #22 and #23 when they described the breaker and the spider box, I _assumed_ that they meant the (very common but not universal) individual breaker for the receptacle yoke in the spider box. I also assumed that if the breaker fed more than one receptacle it would be obvious that there were other loads connected.

-Jonathan
 
R

retirede

Senior Member
Location
Illinois
winnie said:
Ok, I admit I was making guesses based on the OP's description.

In post #21 they are asked if they measured the voltage at the end of the extension cord, and they answered 124V.

In post #22 and #23 when they described the breaker and the spider box, I _assumed_ that they meant the (very common but not universal) individual breaker for the receptacle yoke in the spider box. I also assumed that if the breaker fed more than one receptacle it would be obvious that there were other loads connected.

-Jonathan
Click to expand...

Did we ever establish that the 124V was measured with the load applied or not?
 
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