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#### Sparky1518

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25 mobile homes rated @ 15000 KVA each. What is the minimum size service? Im getting 375A? Please tell me if this is correct or goes to 400A??

This was a test question??

25 x 15000 = 375,000
Table 550.31 Derate @24% 375,000 x .24% = 90,000
90,000/240V = 375A

#### 1.21gigawatts

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400A would be the next standard size up based on your calculation.

#### HARRY304E

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##### RIP 1959-2015
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25 mobile homes rated @ 15000 KVA each. What is the minimum size service? Im getting 375A? Please tell me if this is correct or goes to 400A??

This was a test question??

25 x 15000 = 375,000
Table 550.31 Derate @24% 375,000 x .24% = 90,000
90,000/240V = 375A

550.10 = 50 amps.

Welcome to ET.

#### Sparky1518

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This was a multiple choice question. The answers were

a - 375
b - 400
c - 1600
d - 1800

I stuck between 375 & 400

#### Ultrafault

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##### fertilizer distrubuter
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1.6 million amps.

If you meant 15 kva instead it would be 1600 amps.

#### Sparky1518

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sorry it is 15KVA. Table 550.31 requires a demand factor????

#### HARRY304E

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##### RIP 1959-2015
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sorry it is 15KVA. Table 550.31 requires a demand factor????
Yup, look at the table 22-40=?

#### Sparky1518

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so would the minimum be 375A or 400A?

#### wildleg

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##### animal lover /rat bastard
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however, fwiw, 230.42 says

(B) Specific Installations. In addition to the requirements
of 230.42(A), the minimum ampacity for ungrounded conductors
for specific installations shall not be less than the
rating of the service disconnecting means specified in
230.79(A) through (D).
which, to me, means 400A.

#### dmxtothemax

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Did it say what size the service dissconnect was ?

Whilst most sparkies would probably like a small reserve and go for 400A

But - the question asks what is the "MINIMUM"

So I would say 375 A

#### Sparky1518

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im with you on the minimum? do my calculations look correct?

#### Sparky1518

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it was asking for the minimum service amperage allowed?

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