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PoE Cable Voltage Drop Calculator

Calculate PoE Cat6, Cat5e, and CCA cable voltage drop, delivered terminal voltage, safe run distances, and night-time infrared reboot risks.

Input Parameters

Try Example:
m
1500
W
0.590

Calculation Results

PD Terminal Voltage Gauge (48.00V from 48V PSE)SAFE (>= 44V)
0V37V Min PD44V Safe57V Max
UTP Cable Run Length
65 Meters
UTP Cable Type & Conductor
cat6
PoE Powered Device (PD) Load
8 Watts
PoE Switch Source Voltage (PSE)
48 Volts
DC Loop Resistance per 100m
14 Ω
Total Cable Loop Resistance
9.1 Ω
PoE Line Current
0.167 Amperes
Cable Voltage Drop
1.52 Volts
Voltage Delivered at Camera (PD)
46.48 Volts
Voltage Drop Percentage
3.2 %
Power Loss Dissipated in Cable
0.25 Watts
PoE Voltage Delivery Status
SAFE (Complies with IEEE 802.3af/at)
Field Diagnostic Note
Voltage delivered at device endpoint is highly stable.
Want to compare 2 design options side-by-side (e.g., Scenario A vs Scenario B)?
⚡ CCTV & PoE Hardware Advisory
Switch Managed PoE+ IEEE 802.3at + Kabel UTP Cat6 Pure Copper
HDD Surveillance CMR 24/7 (WD Purple / Seagate SkyHawk)

Use 24/7 CMR surveillance drives in NVRs and solid bare copper Cat6 for PoE runs exceeding 50 meters.

Material Requirement Summary (Copy-Ready)
Ringkasan Jatuh Tegangan (Voltage Drop) Kabel PoE – InfraCalc.web.id
Tipe Kabel      : CAT6 (Hambatan Loop: 14 Ω / 100m)
Panjang Tarikan : 65 meter (Total Hambatan: 9.1 Ω)
Daya Beban      : 8 Watt @ Sumber 48V DC (Arus: 0.1667 A)
Voltage Drop    : 1.52 V (3.2%)
Tegangan Ujung  : 46.48 V DC (Rugi Daya: 0.25 W)
Status Kelayakan: AMAN (Standar IEEE 802.3af/at)
Rekomendasi     : Tegangan di ujung kamera sangat stabil.
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Technical Accuracy Note: Calculation results are engineering estimates based on standard RFC/IEEE/ITU-T models. Actual field performance may vary due to protocol overhead, hardware specifications, and environmental factors.

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How to Use This Tool

  1. Enter the physical cable run length from the PoE switch to the camera endpoint in meters.
  2. Select the cable conductor category (Cat6 Pure Copper, Cat5e Pure Copper, or Copper-Clad Aluminum CCA).
  3. Specify maximum camera power consumption with IR illuminated (Watts) and review delivered terminal voltage.

Worked Example: Standard 65m Cat6 Run 8W Camera

Worked example: A 65m CAT6 cable run for an 8W device powered from a 48V PSE yields a loop resistance of 9.1 Ω and a voltage drop of 1.52V (3.2%). Delivered terminal voltage is 46.48V DC (Status: SAFE (Complies with IEEE 802.3af/at)).

Example Input
Cable Run Length
65 Meters
Cable Conductor Type
Cat6 Pure Bare Copper (~14.0 Ω/100m)
Device Load Power (Watts)
8 Watts
PoE Switch Source Voltage
48V DC (Standard IEEE 802.3af/at Nominal)
Calculated Output
UTP Cable Run Length
65 Meters
UTP Cable Type & Conductor
cat6
PoE Powered Device (PD) Load
8 Watts
PoE Switch Source Voltage (PSE)
48 Volts
DC Loop Resistance per 100m
14 Ω
Total Cable Loop Resistance
9.1 Ω
PoE Line Current
0.167 Amperes
Cable Voltage Drop
1.52 Volts
Voltage Delivered at Camera (PD)
46.48 Volts
Voltage Drop Percentage
3.2 %
Power Loss Dissipated in Cable
0.25 Watts
PoE Voltage Delivery Status
SAFE (Complies with IEEE 802.3af/at)
Field Diagnostic Note
Voltage delivered at device endpoint is highly stable.
Material Requirement Summary (Copy-Ready)
Ringkasan Jatuh Tegangan (Voltage Drop) Kabel PoE – InfraCalc.web.id Tipe Kabel : CAT6 (Hambatan Loop: 14 Ω / 100m) Panjang Tarikan : 65 meter (Total Hambatan: 9.1 Ω) Daya Beban : 8 Watt @ Sumber 48V DC (Arus: 0.1667 A) Voltage Drop : 1.52 V (3.2%) Tegangan Ujung : 46.48 V DC (Rugi Daya: 0.25 W) Status Kelayakan: AMAN (Standar IEEE 802.3af/at) Rekomendasi : Tegangan di ujung kamera sangat stabil.

Core Concept & Engineering Notes

> [!NOTE] > **Normative Standard Compliance ANSI/TIA-568.2-D Clause 6.4.1**: The DC loop resistance values applied by this calculator (Cat6: 14.0 Ω/100m @ 23 AWG solid copper, Cat5e: 18.8 Ω/100m @ 24 AWG solid copper, and CCA: 32.0 Ω/100m non-compliant comparative baseline) adhere to ANSI/TIA-568.2-D and IEEE 802.3af/at standards at 20°C operational baseline. Power over Ethernet (PoE) technology fundamentally streamlines enterprise network and surveillance infrastructure by delivering direct current (DC) electrical power alongside high-speed data packets over structured twisted-pair cabling. In operational deployments, however, the inherent electrical DC loop resistance of metallic conductors induces progressive voltage drop and thermal heat dissipation along the cable trajectory. As current flows from Power Sourcing Equipment (PSE)—such as managed PoE network switches—toward remote Powered Devices (PD) including IP surveillance cameras and outdoor wireless Access Points, a portion of the nominal voltage drops per Ohm's Law (V = I × R). Telecommunication standards such as IEEE 802.3af (PoE 15.4W) and IEEE 802.3at (PoE+ 30W) define 48V–54V DC source outputs while mandating delivered endpoint terminal voltages remain strictly above 37V to 42.5V DC thresholds. A rampant operational failure point stems from deploying budget Copper-Clad Aluminum (CCA) cabling instead of solid bare copper. CCA conductors exhibit a staggering DC loop resistance of 32 Ohms per 100 meters, exceeding Cat6 pure copper (14 Ohms per 100m) by more than 120%. While cameras drawing nominal 4–6 Watts during daylight may operate without obvious symptoms, nightfall triggers high-power infrared (IR) LED illumination (drawing 10–12W). The resulting current surge exacerbates voltage drop, plunging endpoint voltage below operating tolerances and triggering catastrophic reboot loops or video loss. This calculator validates run lengths, conductor metallurgy, and endpoint stability.

How It Was Calculated (Formulas & Steps)

Frequently Asked Questions (FAQ)

Why do PoE CCTV cameras frequently reboot or drop offline specifically at night?

Nightfall triggers automatic infrared (IR) illuminators, surging camera power consumption 2 to 3 times higher. This elevated current doubles the voltage drop along the cable. On lengthy runs or sub-standard CCA cables, endpoint voltage drops below the camera's operational floor, triggering continuous reboot loops.

What is the maximum UTP cable distance for standard PoE without repeaters?

IEEE 802.3 Ethernet standards limit copper cable runs to 100 meters. Spans between 100m and 250m require toggling 'Extend Mode' on the PoE switch (throttling bandwidth to 10 Mbps) with solid Cat6 pure copper. Any distance beyond 250 meters mandates single-mode fiber optic cable.

What are the engineering hazards of using Copper-Clad Aluminum (CCA) cables?

CCA conductors feature a brittle aluminum core that easily fractures under pull tension and suffers over double the electrical resistance of pure copper. In addition to severe voltage drops, CCA cables generate dangerous resistive thermal heating when carrying higher PoE current loads, posing longevity and safety risks.

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References & Notes

Last updated: Technically Verified · Industry Standard

Note: Results above are mathematical estimates based on standard formulas. Always verify against official vendor documentation and site conditions before production deployment.

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🔬 Scientific Methodology & Normative Verification

Engineering Sensitivity Analysis, Response Curve & Technical Citation

✓ Calibrated to ISO/IEC/IEEE/TIA Clauses

1. 1. 3-Point Engineering Sensitivity & Tolerance Envelope

Comparative evaluation across theoretical laboratory bounds (0% loss), current nominal operating point, and conservative field safety bounds (±15% thermal/aging derating).

Evaluated Parameter Ideal Theoretical Bound Nominal Operating Point Conservative Safety Bound (±15%) Engineering Derating Rule
UTP Cable Run Length 58.5 65 74.75 Engineering Safety Margin (+15% Overhead)
PoE Powered Device (PD) Load 7.2 8 9.2 Engineering Safety Margin (+15% Overhead)
PoE Switch Source Voltage (PSE) 43.2 48 55.2 Engineering Safety Margin (+15% Overhead)
DC Loop Resistance per 100m 12.6 14 16.1 Engineering Safety Margin (+15% Overhead)
Total Cable Loop Resistance 8.19 9.1 10.46 Engineering Safety Margin (+15% Overhead)

2. 2. Mathematical Function Curve & Operating Coordinate (x₀, y₀)

MATHEMATICAL RESPONSE CURVE: UTP CABLE RUN LENGTH VS UTP CABLE RUN LENGTH Conservative Engineering Bound (+15% Safety Margin) 26 39 52 65 78 91 104 (x₀=65, y₀=65) Variabel Independen (x): UTP Cable Run Length

3. 3. Physical Constants & Normative Standard Clauses

D_Identify = 250 px/m BS EN 62676-4:2015 (IEC 62676-4)

Minimum Horizontal Pixel Density for Identification (DORI)

Clause 6.5 & Table A.1 (25 / 62 / 125 / 250 px/m) — Video surveillance standard specifies Detection=25 px/m, Observation=62 px/m, Recognition=125 px/m, Identification=250 px/m.

R_loop(Cat6, 20°C) = 14 Ω/100m ANSI/TIA-568.2-D & IEEE 802.3bt

DC Loop Resistance for 23 AWG Solid Copper Cat6

Clause 6.4.1 / Table 145-1 — Nominal 23 AWG solid copper loop resistance at 20°C is 14.0 Ω/100m (TIA maximum ceiling is 18.8 Ω/100m).

α_Cu(20°C) = 0.00393 °C⁻¹ IEC 60028

Temperature Coefficient of Resistance for Copper

International Annealed Copper Standard — Used in thermal derating equation: R(T) = R_20 × [1 + 0.00393 × (T - 20)].

4. 4. Independent Technical & Academic Citation (IEEE / APA 7th / BibTeX / LaTeX)

Use the standard citation formats below to reference this computational methodology in engineering specifications, audit reports, or academic papers.

Format IEEE & APA 7th Edition

[IEEE] KalkuNet Engineering Team, "PoE Cable Voltage Drop Calculator — Standard Engineering Computational Instrument," KalkuNet Technical Suite, 2026. [Online]. Available: https://kalkunet.com/en/tools/poe-voltage-drop-calculator. [Accessed: 2026-11-08].

[APA 7th] KalkuNet Engineering Team. (2026). PoE Cable Voltage Drop Calculator (Production release 2026-11-08) [Engineering computational software]. KalkuNet. https://kalkunet.com/en/tools/poe-voltage-drop-calculator

BibTeX & LaTeX Derivation Snippet
@software{kalkunet_poe_voltage_drop_calculator_2026,
  author = {{KalkuNet Engineering Team}},
  title = {{PoE Cable Voltage Drop Calculator --- KalkuNet Engineering Suite}},
  year = {2026},
  publisher = {KalkuNet.com},
  url = {https://kalkunet.com/en/tools/poe-voltage-drop-calculator},
  urldate = {2026-11-08}
}

% LaTeX Engineering Derivation — Generated via https://kalkunet.com/en/tools/poe-voltage-drop-calculator
\begin{equation}
  \text{Model: } Total Loop Resistance (Ω) = (Resistance per 100m × Run Length m) ÷ 100
\end{equation}
% Parameter Input Terukur: cableLenM = 65, \; cableType = cat6, \; camPowerWatt = 8, \; sourceVoltage = 48
% Hasil Evaluasi Numerik : cableLenM = \mathbf{65}, \; cableType = \mathbf{cat6}, \; camPowerWatt = \mathbf{8}