Electrical Space Heating and Cooling

What section of the code book applies to electric space heating?

Section 62

Are electric space heating loads considered continuous when calculating the demand of the main service for an apartment? What code rule and subrules applies?

1. True

2. Rule 8-202, 2)

When would you use the greater of the loads when determining what loads contribute towards the main service between heating and A/C?

If there are interlocks so only one may be used at a time

If there are no interlocks preventing A/C and heating from running at the same time what do you do when determining how to loads contribute to the main service?

You take the sum of the A/C load and the heating load with the approriate factors from section 62-118 applied.

How would you calculate the demand of electric space heating?

Subtract the first 10kW at 100% demand, then multiply the remainder by 75%, add the product of your 75% of demand with 10kW, the sum is the answer.

Can you supply a heating load with a circuit that also handles lighting? And what code rules correlates to the answer?

1. False

2. Rule 62 - 110s specified that a branch circuit supplied for electric heating devices must solely supplies the power to the heating devices.

Is there a rule that allows you to have multiple heating devices off the same circuit? Which rule?

1. True

2. Rule 62 - 114 2) states that two or more heating devices inside a building for residential occupancy can be connected to a single branch circuit, provided the overcurrent device is not rated above 30A

What % of the breakers ampacity for a heating circuit should the conductors be?

80%

How high can the rating of thge overcurrent device exceed the rating of the conductor by?

125%, If its not a standard rating the device can be sized up

How would you determine the conductor size for a heating unit? and the overcurrent device?

Find the rated current of the heater by dividing its power usage by voltage, then find the conductor size using the termination temperature in table 2, to find the overcurrent device divide the conductor ampacity by 80% as it is only required to be 80% of the breaker then check table 13 for the size of the breaker, subrule 8 of rule 62-114 allows the breaker to be upsized if it is not a standard sizing.

Branch circuits used for continuous duty motors should have an ampacity rating of not less than what % of the rated current of the motor?

125%

How would you size the conductor used for air conditioning?

Divide the power by the voltage for the circuit powering the A/C, then multiply by 125% as the branch circuits supplying continuous use motors must be 125% of the rated current of the motor.