How to Replace a Wire in a POE Camera: 7-Wire Cable

POE cameras can work with 7-wire cable, but this is a non-standard configuration that requires proper connection. In your case with a broken green wire (pin 6), you can use the brown wire instead, but only if you maintain the correct pin configuration for data and power transmission. For negative power supply, a separate wire or pair is usually required, and one wire may not be enough for stable camera operation at a distance of 25 meters.

Contents

• How POE cameras work with 7-wire cable
• POE standards and pin configurations
• Cable repair: replacing broken green wire
• Negative power requirements
• Practical recommendations for your Hikvision camera
• Alternative solutions

How POE cameras work with 7-wire cable

POE (Power over Ethernet) cameras can work with various types of cables, including 7-wire configurations, but this depends on the specific camera model and implementation method. Under standard IEEE 802.3af conditions, POE uses 4 wire pairs in the cable for simultaneous data and power transmission.

In the 7-wire cable you’re using, one of the wire pairs is likely missing. For Hikvision cameras, this is a fairly common situation, as manufacturers sometimes use non-standard wiring to save costs or for specific camera needs.

Important point: Many Hikvision cameras have 10 wires in the cable, but only 8 are used for standard POE connection. Black and white wires are usually intended for 12V DC pigtail (non-standard power connection), as indicated in the Hikvision repair manual.

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POE standards and pin configurations

IEEE 802.3af Standard

The IEEE 802.3af standard provides up to 15.4W of power per port. This standard uses two main power transmission schemes:

Mode A (Alternative A):

• Power is supplied on pairs 1-2 and 3-6
• Used for data and power transmission on a single pair

Mode B (Alternative B):

• Positive potential on pins 4 and 5
• Negative potential on pins 7 and 8
• This mode is more commonly used in passive POE systems

Hikvision Features

Hikvision cameras often use non-standard wiring. As noted in forum discussions, different Hikvision models may have different wire color schemes, so it’s important to check the specific pinout for your camera.

Example standard color scheme for some Hikvision models:

• Pin 1: Yellow
• Pin 2: Orange
• Pin 3: Blue
• Pin 4: Purple
• Pin 5: Gray
• Pin 6: Green
• Pin 7: White
• Pin 8: Brown

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Cable repair: replacing broken green wire

Yes, you can use the brown wire instead of the green one, but with important caveats:

What you can do:

1. Determine wire assignments: Disassemble the RJ45 connector and determine which wire connects to which pin
2. Use brown wire instead of green: If the green wire (pin 6) is broken, you can use the brown wire (pin 8) to connect to the same contact
3. Maintain integrity of other pairs: Ensure that other wire pairs remain properly connected

Important warnings:

• Don’t break pair integrity: Standard Ethernet uses twisted pairs to reduce interference. Breaking a pair can degrade signal quality
• Check compatibility: Some Hikvision models have special wiring requirements, as mentioned in Reddit discussions
• Test after repair: After replacing the wire, be sure to test camera operation

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Negative power requirements

How many wires are needed for power?

For POE power supply, at least one wire for positive potential and one for negative are required. In the IEEE 802.3af standard, typically:

• Positive potential: Pins 4 and 5
• Negative potential: Pins 7 and 8

One wire for negative is insufficient:

One wire for negative power supply is insufficient for several reasons:

1. Current requirements: POE cameras consume significant current, especially at a distance of 25 meters
2. Voltage drop: A long cable creates voltage drop, which increases with resistance
3. Power stability: One wire may not provide sufficient voltage stability for proper camera operation

Recommended solution:

Use a complete wire pair (pins 7 and 8) for power, as provided in the standard Mode B.

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Practical recommendations for your Hikvision camera

Step-by-step repair plan:

1. Disassemble existing connector: Carefully disassemble or cut off the old RJ45 connector
2. Create a pinout diagram: Make a diagram of wire connections to pins
3. Replace green wire: Use the brown wire to connect to pin 6
4. Check pair integrity: Ensure that other pairs remain intact
5. Install new connector: Connect all wires to a new RJ45 connector

Alternative options:

• Use F-F adapter: As recommended on the use-ip.co.uk forum, you can install a new connector and use an adapter
• Complete cable replacement: If the cable is damaged in multiple places, it might be easier to replace it entirely
• Use passive POE injector: If power issues arise, you can use an external injector

Important notes:

• Cable length: 25 meters is an acceptable length for POE, but a damaged cable may cause problems
• Cable quality: Cheap unshielded Cat5e is more susceptible to interference and losses
• Power supply: Ensure your Hikvision DVR provides sufficient power for the camera

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Alternative solutions

If repair doesn’t help:

1. Cable replacement: Purchase a new quality shielded Cat5e or Cat6 cable
2. Use passive POE: Some Hikvision cameras can work with passive POE
3. Separate power supply: If POE doesn’t work, you can use a separate 12V power supply

Preventive measures:

• Use quality cables: Invest in shielded cables for better reliability
• Proper installation: Avoid kinks and mechanical damage to cables
• Regular inspection: Periodically check the condition of cables and connectors

Conclusion

1. POE cameras can work with 7-wire cable, but this requires correct pin configuration
2. Green wire can be replaced with brown, but it’s important to maintain the integrity of other pairs
3. One wire for negative power supply is insufficient - it’s recommended to use a complete pair
4. For your situation, try replacing the green wire with brown, but be prepared for possible signal quality issues
5. The best long-term solution is to use a quality shielded Cat5e or Cat6 cable with proper pin wiring

If you experience power or image quality issues, consider replacing the cable entirely or using an external POE injector to ensure stable operation of your Hikvision camera.

Sources

1. PoE Pinout Explained and Wiring Guide - eufy US
2. Power over Ethernet - Wikipedia
3. Hikvision IP Camera RJ45 Pin-Out (wiring) — SecurityCamCenter.com
4. What pairs are actually needed to power a Hikvision Cam | IP CCTV Forum
5. 802.3af, at and bt: Exploring Active Power Over Ethernet IEEE Standards
6. Understanding the IEEE 802.3af standard - basics of Power over Ethernet
7. Replacing connector on POE IP camera | IP CCTV Forum