test wording

[extclyde]

i am take my administrators test and some of the wording is confusing.
What is a duplex considered- a single or multifamily calculation, codes say multifamily are 3 or more.

Second, on a multifamily calc. it said do not calculate house and laundry in your calculation. Laundry i understand but house?

 

[jtester]

A duplex is two single family dwellings. For example you'd use 220.85 instead of 220.84 in the 2005 NEC.

House loads often include building mounted lighting, landscape power, and other loads not connected to a resident's meter.

Jim T

 

[Rockyd]

House often refers to a separate panel tucked in the mechanical room, or other inconspicuous place (manager's unit apartment). Operates all the stuff, and maybe more, that Jim T referred to.

 

[charlie b]

What is a duplex considered- a single or multifamily calculation. . . .

Neither. Article 100 defines three similar terms: (1) Dwelling, One-Family, (2) Dwelling, Two-Family, and (3) Dwelling, Mulifamily.

For two-family and multifamily dwellings, the important thing to keep straight is whether you are calculating the load for a single dwelling or for the building as a whole. For example, 220.53 lets us use a 75% demand factor, if there are four or more appliances fastened in place.

Suppose that a duplex has a single service that is split into two feeders, with one feeder going to each dwelling unit. You are asked to calculate the load on one of the units. Suppose that each unit had a dishwasher, a disposal, and an electric water heater. That is only three items, so you can?t use the 75% factor.

However, now let us suppose that you are also asked to calculate the service load to the duplex. Now you are looking at two dishwashers, two disposals, and two water heaters. That is six items, and you are allowed to use the 75% factor.