Emerson 8712E manual Powering the Transmitter, Supply Wire Requirements, Disconnects

Quick Installation Guide

00825-0100-4664, Rev BB January 2013

Rosemount 8712 / 8700 Series

Powering the Transmitter

The 8712E transmitter is designed to be powered by 90-250 Vac, 50–60 Hz or 12–42 Vdc. Before connecting power to the Rosemount 8712E consider the following standards and be sure to have the proper power supply, conduit, and other accessories. Wire the transmitter according to national, local and plant electrical requirements for the supply voltage. See Figure 19.

Figure 19. DC Power Supply Current Requirements

Supply Current (Amps)

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

12 18 24 30 36 42

Power Supply (Volts)

I = Supply current requirement (Amps)

V = Power supply voltage (Volts)

Supply Wire Requirements

Use 12 to 18 AWG wire rated for the proper temperature of the application. For connections in ambient temperatures above 140 °F (60 °C), use a wire rated for 176 °F (80 °C). For ambient temperatures greater than 176 °F (80 °C), use a wire rated for 230 °F (110 °C). For DC powered transmitters with extended cable lengths, verify that there is a minimum of 12 V DC at the terminals of the transmitter.

Disconnects

Connect the device through an external disconnect or circuit breaker. Clearly label the disconnect or circuit breaker and locate it near the transmitter and per local electrical control.

Installation Category

The installation category for the 8712E is (Overvoltage) Category II.

Overcurrent Protection

The Rosemount 8712E transmitter requires overcurrent protection of the supply lines. Maximum ratings of overcurrent devices are shown in Table 10.

Table 10. Overcurrent Limits

Power System	Fuse Rating	Manufacturer
95-250 V AC	2 Amp, Quick Acting	Bussman AGC2 or Equivalent
12-42 V DC	3 Amp, Quick Acting	Bussman AGC3 or Equivalent

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