28.02.2013 Views

Building Design and Construction Handbook - Merritt - Ventech!

Building Design and Construction Handbook - Merritt - Ventech!

Building Design and Construction Handbook - Merritt - Ventech!

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

TABLE 15.2 Protection of Single-Phase Motors <strong>and</strong> Circuits (Continued)<br />

Size of motor<br />

Horsepower<br />

15.37<br />

Ampere<br />

rating<br />

Maximum<br />

size fuse<br />

permitted<br />

by the<br />

code<br />

Branch-circuit<br />

protection*<br />

Time-delaycartridge<br />

or low-peak<br />

fuse that<br />

can be<br />

used<br />

Ordinary<br />

service<br />

230 V<br />

1 ⁄6 2.2 15 3 1 ⁄2 2 1 ⁄4 2 1 ⁄2 2 8 ⁄10 2 8 ⁄10<br />

1 ⁄4 2.9 15 5 2 8 ⁄10 3 2 ⁄10 4 3 1 ⁄2 30 30 00 14 R 1 ⁄2<br />

1 ⁄3 3.6 15 6 3 1 ⁄2 4 4 1 ⁄2 4 1 ⁄2<br />

1 ⁄2 4.9 15 8 5 5 6 ⁄10 6 1 ⁄4 6 1 ⁄4<br />

3 ⁄4 6.9 25 12 7 8 9 8 30 30 00 14 R 1 ⁄2<br />

1 8 25 15 8 9 10 10<br />

1 1 ⁄2 10 30 17 1 ⁄2 10 12 12 12 30 30<br />

2 12 40 20 12 15 15 15 60 30 0 14 R 1 ⁄2<br />

3 17 60 25 17 1 ⁄2 20 20 20 60 30 1 10 R 3 ⁄4<br />

5 28 90 45 30 35 35 35 100 60 2 8 R 3 ⁄4<br />

7 1 ⁄2 40 125 60 40 45 50 50 200 60 2 6 R 1<br />

10 50 150 80 50 60 70 60 200 100 3 4 R 1 1 ⁄4<br />

* These do not give motor-running protection.<br />

† On normal installations these also give branch-circuit protection.<br />

Motor-running protection†<br />

Size of time-delay-cartridge<br />

or low-peak fuse<br />

Maximum size<br />

Heavy<br />

service<br />

40�C<br />

motor<br />

All other<br />

motors<br />

Size of fused switch<br />

or fuse holder<br />

Maximum<br />

size<br />

switch<br />

that can<br />

be used<br />

Size that<br />

can be<br />

used with<br />

time-delaycartridge<br />

or lowpeakfuses<br />

Minimum<br />

size of<br />

starter:<br />

NEMA<br />

size<br />

Minimum<br />

size <strong>and</strong><br />

type of<br />

wire:<br />

AWG<br />

or<br />

MCM<br />

Minimum<br />

size of<br />

conduit:<br />

diameter, in

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!