#### throttlebody

##### Senior Member

- Location
- Martinsburg, WV

1) What is the load demand for a mobile home park with 35 sites?

Indexing refers to 550.18, 550 III, and 550.31

550.18 is for calculations based on each site supply cord service feeder.

550.31 is what is needed, I believe.

Demand for 35 sites is calculated on #1 or #2 of 550.31

#2 sq ft is unknown, so I assume that 16000VA is the minimum demand for each lot.

Table 550.31 is the allowance for 35 sites equalling 24% total demand load.

16000VA x 35 x .24DF = 134,400VA total

or

134,400VA/240v= 560Amps total

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2) What is the DC resistance of 420ft of 6AWG cu?

#6 on table 8 has a DC resistance of .491 p/1000ft

We need the resistance of 420ft

R = 420ft x .491ohms/1000ft = 0.20622

or

.491/1000 = 0.000491ohms p/ft x 420ft = 0.20622 ohms

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3) What is the lighting and receptacle demand load for a 2100sq ft dwelling, with 34 complimentary receptacles and 12 lights rated at 100watts each.

220.14 (I) refers to (J) and (K) in which no additional load be added for receptacles of dwelling units or for lights specified in 210.70 (A) and (B).

2100sq ft x 3va = 6300va

3000va x 100% = 3000va

3300va x 35% = 1155va

4155va total demand load.

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4) What is the demand load of a single phase AC 5hp motor @ 230v and 3 - 120v Electric Base Board Heaters @ 3KW?

When figuring demand between AC and Heating equipment, the demand load would go by the largest of the 2? I might be reading too far into this one. They may be asking for a total demand of both together. Also,I am confused as to which formula for the motor to use.

Heat

3 x 1000/240 = 12.5Amps

AC

5hp x 746/230 = 16.2Amps

or

Table 430.248 28FLC Amps x 125% = 35Amps ??