Installation of Industrial Machines

As I noted in my 2012 December blog, for 2013 I intend to focus more on installation issues.  The first topic for 2013 is on Industrial Machines.

Industrial machines are defined as a power-driven machine that is used to process material by cutting; forming; pressure; electrical, thermal, or optical techniques; lamination; or a combination of these processes, and can include associated equipment used to transfer material or tooling, including fixtures, to assemble/disassemble, to inspect or test, or to package [NFPA 79-2012].  Industrial Machines come in many different sizes, shapes, operating characteristics and incorporate a variety of components including power, control, monitoring, signaling, heating, movement and measurement.  Industrial Machines encompass a large category of equipment, but they do not include hand-held or portable devices.

For equipment that is installed in the US, the manufacturer should have their Industrial Machines evaluated to Electrical Standard for Industrial Machinery [NFPA 79].  If the Industrial Machine is intended for use outside of the US, many countries have adopted Safety of machinery – Electrical Equipment of Machines – Part 1: General Requirements [IEC 60204-1] as the standard used to evaluated Industrial Machines. 

While evaluation to consensus standards such as Electrical Standard for Industrial Machinery [NFPA-79] is not mandatory in the US, installers are required to meet the minimum requirements detailed with the National Electric Code [NFPA 70].

The National Electric Code has three main requirements for Industrial Machinery.  The first requirement is that the Industrial Machine be provided with a permanent nameplate.  The nameplate shall have the following information:

1. Supply voltage, number of phases, frequency, and full-load current
2. Maximum ampere rating of the short-circuit and ground-fault protective device
3. Ampere rating of largest motor
4. Short-circuit current rating (SCCR) of the machine industrial control panel
5. Electrical diagram number(s) or the number of the index to the electrical diagrams

The second requirement addresses the requirements for the supply conductors and the overcurrent protective device.  These requirements are:

1. The supply conductor shall have an ampacity that is the sum of:
1. 125 percent of all resistive heating loads
2. 125 percent of the highest rated motor load
3. 100 percent of all connected loads
2. The Industrial Machine shall have a disconnecting means
3. The Industrial Machine shall have overcurrent protection, whether contained integral or external to the device

The third requirement is that the Industrial Machine shall not be installed where the available fault current exceeds the short-circuit current rating as marked on the nameplate of the Industrial Machine.

Installing an Industrial Machine to the requirements of the National Electric Code [NFPA 70] will limit the potential for overcurrent conditions to damage the facility.  To provide personnel protection from normal and abnormal operating conditions of the Industrial Machine, Electrical Standard for Industrial Machinery [NFPA-79] provides more comprehensive requirements.  Some of the requirements include:

• Disconnect and overcurrent protection
• Grounding and bonding
• Power system interactions
• Internal and external conductor sizes, colors, and routing
• Control system performance and safety
• Enclosure types, openings, spacings, and guarding
• Labeling and documentation

For more information, please contact me by commenting on this blog or sending me an e-mail.