Wiring Best Practices

Introduction

There are several rules that must be followed when wiring the TM5 System.

Wiring Rules

DANGER
	HAZARD OF ELECTRIC SHOCK, EXPLOSION OR ARC FLASH Disconnect all power from all equipment including connected devices prior to removing any covers or doors, or installing or removing any accessories, hardware, cables, or wires except under the specific conditions specified in the appropriate hardware guide for this equipment. Always use a properly rated voltage sensing device to confirm the power is off where and when indicated. Replace and secure all covers, accessories, hardware, cables, and wires and confirm that a proper ground connection exists before applying power to the unit. Use only the specified voltage when operating this equipment and any associated products. Failure to follow these instructions will result in death or serious injury.

DANGER

HAZARD OF ELECTRIC SHOCK, EXPLOSION OR ARC FLASH

Disconnect all power from all equipment including connected devices prior to removing any covers or doors, or installing or removing any accessories, hardware, cables, or wires except under the specific conditions specified in the appropriate hardware guide for this equipment.
Always use a properly rated voltage sensing device to confirm the power is off where and when indicated.
Replace and secure all covers, accessories, hardware, cables, and wires and confirm that a proper ground connection exists before applying power to the unit.
Use only the specified voltage when operating this equipment and any associated products.

Failure to follow these instructions will result in death or serious injury.

The following rules must be applied when wiring the TM5 System:

I/O and communication wiring must be kept separate from the power wiring. Route these 2 types of wiring in separate cable ducting.
Verify that the operating conditions and environment are within the specification values.
Use proper wire sizes to meet voltage and current requirements.
Use copper conductors only.
In the case of TM5 Safety-related I/O modules:
- Use twisted pair, shielded cables for analog, expert, or fast I/O and TM5 bus signals.
- Use twisted pair, shielded cables for encoder, networks and Sercos III bus.

Sercos Cable Characteristics

Cable characteristics of the Sercos cable (see the Schneider Electric catalog for the various cables available):

Property	Value
Voltage isolation (jacket)	300 Vdc
Temperature range	-20...+60 °C / -4...+140 °F
Cable diameter	5.8 ± 0.2 mm (0.23 ± 0.008 in.)
Bending radius	8 x diameter (fixed routing)
Sheath	PVC, flame-retardant
Cable type and shielding	CAT6 with S/FTP (Sercos III)

TM5 Safety I/O Wiring

WARNING
	UNINTENDED EQUIPMENT OPERATION Use shielded cables for all fast I/O, analog I/O and communication signals. Ground cable shields for all analog I/O, fast I/O and communication signals at a single point¹. Route communication and I/O cables separately from power cables. Failure to follow these instructions can result in death, serious injury, or equipment damage.

¹Multipoint grounding is permissible if connections are made to an equipotential ground plane dimensioned to help avoid cable shield damage in the event of power system short-circuit currents.

To ground the shielded cables, refer to the section Grounding the TM5 System.

This table provides the wire sizes to use with the removable terminal block TM5ACTB52FS:

This table provides the wire sizes to use with the removable terminal blocks TM5ACTB5EFS and TM5ACTB5FFS:

DANGER
	FIRE HAZARD Use only the correct wire sizes for the maximum current capacity of the I/O channels and power supplies. For relay output (2 A) wiring, use conductors of at least 0.5 mm² (AWG 20) with a temperature rating of at least 80 °C (176 °F). For common conductors of relay output wiring (7 A), or relay output wiring greater than 2 A, use conductors of at least 1.0 mm² (AWG 16) with a temperature rating of at least 80 °C (176 °F). Failure to follow these instructions will result in death or serious injury.

DANGER

FIRE HAZARD

Use only the correct wire sizes for the maximum current capacity of the I/O channels and power supplies.
For relay output (2 A) wiring, use conductors of at least 0.5 mm² (AWG 20) with a temperature rating of at least 80 °C (176 °F).
For common conductors of relay output wiring (7 A), or relay output wiring greater than 2 A, use conductors of at least 1.0 mm² (AWG 16) with a temperature rating of at least 80 °C (176 °F).

Failure to follow these instructions will result in death or serious injury.

The spring clamp connectors of the terminal block are designed for only one wire or one cable end. Two wires to the same connector must be installed with a double wire cable end to help prevent loosening.

DANGER
	LOOSE WIRING CAUSES ELECTRIC SHOCK Do not insert more than one wire per connector of the spring terminal blocks unless using a double wire cable end (ferrule). Failure to follow these instructions will result in death or serious injury.

TM5 Terminal Block

Inserting an incorrect terminal block into the electronic module can cause unintended operation of the application and/or damage the electronic module.

DANGER
	ELECTRIC SHOCK OR UNINTENDED EQUIPMENT OPERATION Connect the terminal blocks to their designated location. Failure to follow these instructions will result in death or serious injury.

NOTE: To help prevent a terminal block from being inserted incorrectly, ensure that each terminal block and electronic module is clearly and uniquely coded.

TM5 Strain Relief Using Cable Tie

There are 2 methods to reduce the stress on cables:

The terminal blocks have slots to attach cable ties. A cable tie can be fed through this slot to secure cables and wires to reduce stress between them and the terminal block connections.
After grounding the TM5 System by means of the grounding plate TM2XMTGB, wires can be bundled and affixed to the grounding plate tabs using wire ties to reduce stress on the cables.

The following table provides the size of the cable tie and presents the two methods to reduce the stress on the cables:

Cable Tie Size	Terminal Block	TM2XMTGB Grounding Plate
Thickness	1.2 mm (0.05 in.) maximum	1.2 mm (0.05 in.)
Width	4 mm (0.16 in.) maximum	2.5...3 mm (0.1...0.12 in.)
Mounting illustration

WARNING
	ACCIDENTAL DISCONNECTION FROM PROTECTIVE GROUND (PE) Do not use the TM2XMTGB Grounding Plate to provide a protective ground (PE). Use the TM2XMTGB Grounding Plate only to provide a functional ground (FE). Failure to follow these instructions can result in death, serious injury, or equipment damage.

Protecting Outputs from Inductive Load Damage

Depending on the load, a protection circuit may be needed for the outputs on the controllers and certain modules. Inductive loads using DC voltages may create voltage reflections resulting in overshoot that will damage or shorten the life of output devices.

WARNING
	INDUCTIVE LOADS Use an appropriate external protective circuit or device to reduce the risk of inductive direct current load damage. Failure to follow these instructions can result in death, serious injury, or equipment damage.

If your controller or module contains relay outputs, these types of outputs can support up to 240 Vac. Inductive damage to these types of outputs can result in welded contacts and loss of control. Each inductive load must include a protection device such as a peak limiter, RC circuit or flyback diode. Capacitive loads are not supported by these relays.

NOTE: In the TM5 Safety-Related System, relay outputs can support up to 48 Vac (TM5SDM4DTRFS) and up to 230 Vac (TM5SDO2DTRFS).

WARNING
	RELAY OUTPUTS WELDED CLOSED Always protect relay outputs from inductive alternating current load damage using an appropriate external protective circuit or device. Do not connect relay outputs to capacitive loads. Failure to follow these instructions can result in death, serious injury, or equipment damage.

Protective circuit A: this protection circuit can be used for both AC and DC load power circuits.

C Value from 0.1 to 1 μF

R Resistor of approximately the same resistance value as the load

Protective circuit B: this protection circuit can be used for DC load power circuits.

Use a diode with the following ratings:

Reverse withstand voltage: power voltage of the load circuit x10.
Forward current: more than the load current.

Protective circuit C: this protection circuit can be used for both AC and DC load power circuits.

In applications where the inductive load is switched on and off frequently and/or rapidly, ensure that the continuous energy rating (J) of the varistor exceeds the peak load energy by 20 % or more.