Answer:
Explanation:
We should know that, Power is given as
P = IV
Where
P is power in watts
I is current in amps
And V is potential difference in Volts
The circuit breaker is design to be
240V, 60A.
So current above 60A will trip the circuit breaker off. Circuit breaker trips OFF when much current is flowing through the breaker.
Now,
The furnace that do trip the circuit breaker off has three heating element each of 5000W
And this element do not trip ON at once it is stage by stage.
When the first element is ON, the current it will draw from the MAINS is
We know that the first heating element has a power rating of 3000W.
P = IV
I' = P/V = 3000 / 240
I' = 20.833Amps
The circuit breaker is still OK with this because it has a capacity of 60A
After a while, the second, the second heating element is trip ON
And this will also draws a current of
I'' = P/V = 3000/240
I'' = 20.833amps
So, the total current drawn now is
I = I' + I" = 20.833 + 20.833
I = 41.667 amps
Again, the circuit breaker is still okay with this because it has a 60A capacity
After a while again, the third element is trip ON and this will also draw current of
I"' = P/V = 3000/240
I"' = 20.833 amps
Now, the total current drawn is
I = I' + I" + I"'
I = 20.833+20.833+20.833
I = 62.5 Amps
Wow, this is above the circuit rating of the breaker, then it will trip off.
Recommendation
I will recommend they get a new circuit breaker of higher capacity maybe 240V, 80-100A circuit breaker, since changing the furnace might cause a fortune.
