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PYXIS Engineering Corporation |
PYXIS
ENGINEERING CORPORATION 3839 Bret Harte Drive Redwood City, CA 94061-1115 TEL 650/365-2694 FAX 650/365-2695 NET tom AT pyxiseng.com |
Industrial
Electrical Engineering allows construction of efficient and safe machines.
The
checklist below is helpful in identifying common requirements for industrial
machines.
PLEASE NOTE THAT THE CURRENT NFPA 79 EDITION IS 2002 –
BUT THIS CHECKLIST MAY STILL HELP!
General Checklist for Inspection
Standard NFPA 79
Electrical Standard for Industrial Machinery,
1994 Edition
|
Item |
NFPA
79 Paragraph |
Description |
OK |
Check |
|
1. |
4.2.1 |
Diagrams showing the electrical circuits of the machine. |
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2. |
4.2.2 |
Diagram cross references for relays, switches, etc. |
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3. |
4.2.4 |
Switch symbols shown with utilities off and machine in normal
starting condition. |
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4. |
4.2.5 |
Interconnected conductors shown with same alphanumeric reference, except
smaller than AWG#18 in electronic assemblies. |
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5. |
4.2.7 |
Interconnecting diagrams for separate enclosures of large systems. |
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6. |
4.2.9 |
Plug/receptacle pin identification. |
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7. |
4.3 |
Operating instructions, maintenance instructions, spare parts list. |
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8. |
4.4 |
Durable identification plates. |
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9. |
4.5 |
Warning label if disconnect does not de-energize all exposed live
parts when in OFF position. |
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10. |
4.6 |
Machine builders name, trademark, or other identification symbol. |
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11. |
4.7 |
Permanent nameplate listing, in English, clearly identifying machine
serial number, supply voltage, phase, frequency, full-load current, ampere rating
of largest motor load. |
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12. |
4.8 |
Additional identification provided if the nameplate is not easy to
read. |
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13. |
4.9 |
Functional identification for control devices, i.e. HAND-OFF-AUTO
etc. |
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14. |
5.2 |
Devices properly rated for temperature, altitude, humidity, and
supply voltage. |
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15. |
6.2 |
Live parts greater than 30 volts protected by insulation or
enclosures. |
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16. |
6.2 |
Electrical equipment and machine members grounded and bonded. |
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17. |
6.3 |
Circuits less than 30 volts separated from higher voltage circuits. |
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18. |
6.4 |
Safeguarding from residual voltages where present. |
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19. |
7.1,2,3 |
Properly rated disconnecting means provided for each incoming supply circuit. |
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20. |
7.4,8 |
Disconnecting means properly mounted, and open and closed position of
disconnecting means identified. |
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21. |
7.5 |
Disconnecting means opens all ungrounded conductors of single supply
circuit simultaneously. |
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22. |
7.8.2 |
Multiple disconnecting means grouped together. |
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23. |
7.9 |
Disconnecting means mechanically or electrically interlocked with
enclosure doors. Exception allowed if
warning label attached and tool required to open enclosure. |
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24. |
7.10 |
Disconnecting handle readily accessible. |
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25. |
7.11 |
Attachment plug and receptacle for two horsepower or less, only. |
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26. |
8.1,2,3 |
Overcurrent protection for supply conductors, and machine wiring
(breaker, fuse, etc.). |
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27. |
8.5 |
Motor branch circuits have proper overload protection. |
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28. |
8.6 |
Motor overload device in all phases to protect from motor overloads. |
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29. |
8.8 |
Resistance heating elements rated not over 48 amps. Special arrangements required for over 48
amp heaters. |
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30. |
8.9 |
Motor control circuit conductors and transformers properly protected. |
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31. |
8.11 |
Large power transformer circuits properly protected on primary and
secondary. |
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32. |
8.12 |
Control circuit transformer properly protected. |
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33. |
8.14 |
Proper undervoltage protection for machinery that will malfunction
below minimum voltage. |
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34. |
9.1 |
Control circuit source of supply taken from load side of main disconnecting
means. |
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35. |
9.5 |
Stop circuits provided and function correctly. |
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36. |
9.6,8,9,10 |
Start circuits include safety measures. |
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37. |
10.2 |
Control components and wiring accessible within panels. |
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38. |
12.1 |
Control equipment located so that it will not interfere with machine
adjustments or maintenance. |
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39. |
13.1 |
Pushbuttons and switches properly color coded. |
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40. |
14 |
Associated lighting and receptacles properly installed if provided. |
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41. |
15,16,17,
18,19 |
Circuits and wiring in accordance with the National Electric Code and
all local codes. |
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42. |
20.3 |
Programmable controllers shall be protected to require special people
and equipment to modify. |
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43. |
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Operational check. Equipment
operates properly and in accordance with established intent. |
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