EOL resistor color code
Color bands for an end-of-line resistor on a supervised access-control or intercom zone, or the value of a part already in the can.
EOL resistor color code
Bands for a value on the truck, or the value of a resistor already in the can. The required value comes from the panel documentation.
Inputs
Direction
Value
Common EOL values
Results
Resistance 2.2 kΩ
Resistance
2.2 kΩ
Value
Compact
2.2 kΩ
Ohms
2200 Ω
Tolerance
±5%
Drawn bands
- Band 1: Red, Digit. First digit 2
- Band 2: Red, Digit. Second digit 2
- Band 3: Red, Multiplier. Multiplier × 100
- Band 4: Gold, Tolerance. Tolerance ±5%
Band list
Band 1 · Digit
Red — First digit 2
Band 2 · Digit
Red — Second digit 2
Band 3 · Multiplier
Red — Multiplier × 100
Band 4 · Tolerance
Gold — Tolerance ±5%
E24 series
On the series
Yes
Nearest
2.2 kΩ
Below
2 kΩ
Above
2.4 kΩ
Closest series and parallel pairs from the on-hand list. Panel documentation and the AHJ decide whether a combination is acceptable.
Closest pairs
Closest series
1 kΩ + 1 kΩ
Series result
2 kΩ
Series error
−9.09%
Closest parallel
4.7 kΩ ∥ 4.7 kΩ
Parallel result
2.35 kΩ
Parallel error
+6.82%
Worked example
2.2 kΩ at 5% on a four-band part is red, red, red, gold. The same 2.2 kΩ at 1% on a five-band part is red, red, black, brown, brown.
How to use
- The required resistance comes from the panel documentation. Enter that value, or read the bands on a part already in the can.
- Value to bands encodes the ohms, band count, and marked tolerance. Four-band parts use two digits and a multiplier. Five- and six-band parts use three digits.
- Bands to value reads from the digit end toward the tolerance band. The tolerance band is usually set apart. Gold or silver is always the tolerance band.
- The combination helper lists the closest series pair and the closest parallel pair from the on-hand list. Panel documentation and the AHJ decide whether a combination is acceptable.
Assumptions
- Band colors follow IEC 60062. Display colors on the drawn resistor are for reading the graphic, not a second code.
- The required value is the value in the panel documentation. This page does not pick a value for a zone.
- Marked tolerance is a manufacturing specification. It is not a field measurement of the part on the bench.
- E24 neighbors are named at 5% and 10%. E96 neighbors are named at 1% and the tighter listed tolerances.
- The result is an estimate. Manufacturer data, the AHJ, and current applicable code govern material and whether a circuit is energized.
FAQ
- Which end is the first band?
- Read from the digit end toward the multiplier and tolerance. The tolerance band is usually set apart from the others. Gold or silver is a multiplier or tolerance color, never a digit, so a gold or silver band at the start means the part is being read the other way.
- What do the numbers do if the installed value is not the documented value?
- A supervised zone compares the circuit to a voltage or resistance window in the panel. A different resistance moves the circuit relative to that window. Whether the zone reports normal, trouble, or alarm depends on where the reading sits against the programmed thresholds.
- When is a 1% part’s manufacturing window narrower than a 5% part?
- Marked tolerance is a manufacturing range around the nominal value. A 2.2 kΩ 1% part is specified between 2.178 kΩ and 2.222 kΩ. A 2.2 kΩ 5% part is specified between 2.09 kΩ and 2.31 kΩ. The 1% range is the narrower of those two specifications.
- Where does the resistor belong on the zone?
- The end-of-line resistor belongs at the device, at the far end of the supervised pair. A resistor on the panel terminals only covers the wiring up to those terminals.
Disclaimer
Field estimate only. Manufacturer data, the authority having jurisdiction (AHJ), and current applicable code govern material and whether a circuit is energized. See the disclaimer.