Check a series circuit's current and voltage against L-823 cable connector ratings, with contact voltage drop and loss.
Every fixture on a series circuit adds mated connectors to the current path. This tool checks the circuit against the rated current and voltage of the two L-823 connector types, shows the worst-case contact drop and heat the connectors are allowed to produce, and turns a field millivolt reading into a contact resistance you can accept or reject.
Type I is the usual choice for a series primary. Type II suits low-voltage secondary and fixture leads.
For a primary, the highest CCR output voltage, for example from Calculator #14.
For example two primary connectors per fixture. Set 0 to skip the totals.
The specification limit applies at rated current. At a lower current the check works on contact resistance instead.
| Type | Rated current (A) | Current loading (%) | Rated voltage (V) | Voltage loading (%) | Status |
|---|
Quick answers on checking a series circuit against L-823 connector ratings.
It checks a series circuit's current and voltage against the rated current and voltage of the two L-823 connector types. It also shows the worst-case contact drop and heat that the connectors are allowed to produce, and turns a field millivolt reading into a contact resistance you can accept or reject.
Type I is a 1-conductor connector rated 25 A and 5,000 V, and it is the usual choice for a series primary. Type II is a 2-conductor connector rated 20 A and 600 V between contacts, and also 1,500 V to ground, and it suits low-voltage secondary and fixture leads. Class A connectors are factory moulded to the cable and Class B are field attached. A connector must not be moulded to a cable with a higher voltage rating than the connector.
Current loading is the circuit current divided by the rated current, and voltage loading is the maximum voltage divided by the rated voltage. Both must be at or below 100 percent for the connector to be suitable. For a primary, use the highest CCR output voltage, for example from Calculator #14.
The specification limits the drop across a mated contact pair while it carries rated current, so the largest acceptable resistance is the drop limit divided by the rated current. Type I allows 7.5 mV at 25 A and Type II allows 6.0 mV at 20 A, which is 0.30 milliohms for both.
The drop is the number of mated connectors times k times the current times the maximum contact resistance, and the loss is the number of connectors times k times the current squared times the maximum resistance. Here k is the contact pairs in the current path, 1 for Type I and 2 for Type II because current passes through both pins. This is the worst case a compliant connector may produce, not what a good one will.
The measured resistance is the measured millivolt drop divided by the test current, and the reading passes if the resistance is at or below the maximum. The specification limit applies at rated current, so at a lower current the check works on contact resistance instead.
A Type I connector at 6.6 A and 840 V is loaded 26.4 percent on current and 16.8 percent on voltage. The maximum contact resistance is 0.30 milliohms, which is 1.98 mV per connector at 6.6 A. For 200 connectors the circuit drop is 0.40 V and the loss is 2.61 W. A reading of 1.5 mV at 6.6 A is 0.227 milliohms, which passes.
It does not model ageing, corrosion, thermal rise or connector fit, and it holds no ICAO or IEC connector data. Ratings follow FAA AC 150/5345-26E, so confirm the edition in force and the manufacturer's certified data, which may state stricter limits than the specification. Contact resistance also rises with ageing and contamination, so a connector that passes today is not guaranteed to pass later.
Every step is shown so the result can be checked by hand.
Both must be at or below 100 % for the connector to be suitable. Type II is checked against its 600 V rating between contacts, and it is also rated 1500 V to ground.
The specification limits the drop across a mated contact pair while it carries rated current, so the largest acceptable resistance follows from that.
Type I allows 7.5 mV at 25 A, and Type II allows 6.0 mV at 20 A, which is 0.30 mΩ for both.
Here n is the number of mated connectors, and k is the contact pairs in the current path: 1 for Type I, and 2 for a Type II connector because current passes through both pins. This is the worst case a compliant connector may produce, not what a good one will.
The reading passes if the resistance is at or below R_max.
| Item | Type I | Type II |
|---|---|---|
| Conductors | 1 | 2 |
| Rated current | 25 A | 20 A |
| Rated voltage | 5000 V | 600 V |
| Contact drop limit | 7.5 mV | 6.0 mV |
Class A connectors are factory moulded to the cable and Class B are field attached. A connector must not be moulded to a cable with a higher voltage rating than the connector.
| Item | Value |
|---|---|
| Type I, 6.6 A, 840 V | 26.4 % / 16.8 % |
| R_max | 0.30 mΩ |
| Drop per connector at 6.6 A | 1.98 mV |
| 200 connectors | 0.40 V, 2.61 W |
| Reading 1.5 mV at 6.6 A | 0.227 mΩ, passes |
It does not model ageing, corrosion, thermal rise or connector fit, and it holds no ICAO or IEC connector data. A manufacturer's data sheet may state stricter limits than the specification, so use it where it does. Contact resistance in service also rises with ageing and contamination, so a connector that passes today is not guaranteed to pass later.
FAA AC 150/5345-26 (L-823 plug and receptacle, cable connectors), AC 150/5345-7 (L-824 cable) and AC 150/5345-47 (series isolation transformers, whose leads use these connectors). ICAO Aerodrome Design Manual, Doc 9157, Part 5. Use the current edition of each.
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