ON, OFF, TRIP Indication Lamp Wiring Connection

Hi, in this article we are going to see the Indication Lamp or Pilot Lamp connection to indicate ON, OFF, and TRIP. In every electrical panel, motor starter, light control panel, and power control panel you may notice these pilot lamps or indicator lamps are used. Generally, most of the electrical panels use pilot lamps to indicate ON and OFF. But the motor controller or motor starter uses an indicator lamp to show whether the motor is Tripped due to any fault.

Purpose of using Indicator Lamps

1. To indicate whether a breaker is On or off.

2. To indicate whether a circuit is energized or not.

3. To indicate whether power is available in a panel or not.

4. To indicate it is safe to touch a panel or circuit.

5. To indicate when a motor or breaker is tripped.

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Indicator Lamp Colour

Different industries use different standards for indicator lamp colour. It has mostly seen that,

For a Power Control Panel,

ON - Red Colour

OFF - Green Colour

TRIP - Yellow Colour

For a Motor Control Panel,

Running - Green Colour

Stop - Red Colour

Trip - Yellow Colour

For Phase Indication,

'R' Phase - Red Colour

'Y' - Yellow Colour

'B' - Blue Colour

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Indication Lamp Connection

Here you can see the connection of indicator lamps in a DOL Starter having a Thermal Overload Relay.

Step 1

Connect the neutral wire to all indication lamps as shown in the below figure.

Step 2

Connect the NO and NC contacts of the contactor with the 'R' phase as shown in the below figure.

Step 3

Connect the NO contact of the thermal overload relay with the 'R' phase as shown in the below figure.

Step 4

Connect the NO contact terminal of the contactor with the Red indication lamp as shown in the below figure.

Step 5

Connect the NC contact terminal of the contactor with the Green indication lamp as shown in the below figure.

Step 6

Connect the NO contact terminal of the thermal overload relay with the yellow indication lamp as shown in the below figure.

Step 7

Finally, check all the connections as shown in the below figure, if all are connected properly.

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Working Principle

So, you can see that the Red indication lamp is connected to the NO contact, so it will glow when the contactor will be turned on.

As the green indication lamp is connected with the NC contact, so it will glow when the contactor is in off condition.

As the yellow indication lamp is connected with NO contact of the thermal overload relay, so it will glow when the relay senses motor drawing overcurrent or there is any overload fault in the circuit.

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