Emerson ROC827 Power Installation Requirements, Grounding Installation Requirements

ROC827 Instruction Manual

2.1.4 Power Installation Requirements

Be sure to route power away from hazardous areas, as well as sensitive monitoring and radio equipment. Local and company codes generally provide guidelines for installations. Adhere rigorously to all local and National Electrical Code (NEC) requirements.

The removable terminal blocks accept 12 American Wire Gauge (AWG) or smaller wiring.

Although the ROC827 can operate on different DC voltages based on the installed Power Input module, it is good practice when using a battery- backed system to install a low-voltage cutoff device to help protect batteries and other devices the ROC827 does not power. Similarly, when the ROC827 uses a PM-24 Power Input module with a 24 V dc battery- backed system, it is a good practice to install an appropriate low voltage cutoff device to protect the battery back-up.

2.1.5 Grounding Installation Requirements

If your company has no specific grounding requirements, install the ROC827 as a floating system (unconnected to ground). Otherwise, follow your company’s specific grounding practices. However, if you are making a connection between a grounded device and the ROC827 EIA-232 (RS-

232)port, ground the ROC827 Power Input module either by connecting the PM-12’s BAT– to ground or by connecting either of the PM-24’s negative Power Inputs to ground.

The National Electrical Code (NEC) governs the ground wiring requirements. When the equipment uses a DC voltage source, the grounding system must terminate at the service disconnect. All equipment grounding conductors must provide an uninterrupted electrical path to the service disconnect. This includes wire or conduit carrying the power supply conductors.

ƒThe National Electrical Code Article 250-83 (1993), paragraph c, defines the material and installation requirements for grounding electrodes.

ƒThe National Electrical Code Article 250-91 (1993), paragraph a, defines the material requirements for grounding electrode conductors.

ƒThe National Electrical Code Article 250-92 (1993), paragraph a, provides installation requirements for grounding electrode conductors.

ƒThe National Electrical Code Article 250-95 (1993) defines the size requirements for equipment grounding conductors.

Improper grounding or poor grounding practice can often cause problems, such as the introduction of ground loops into your system. Proper grounding of the ROC827 helps to reduce the effects of electrical noise on the ROC827’s operation and protects against lightning.

Issued Mar-06 Installation and Use 2-4