UL 486A, 486B, 486C, 467 and 6703 Explained: Which Listing an Electrical Connector Needs, and What Each One Actually Tests
Sep 10, 2026
Summary: UL 486A covers connectors for copper conductors, UL 486B for aluminum, UL 486C for splicing connectors, UL 467 for grounding and bonding equipment, and UL 6703 for photovoltaic connectors. A connector marked cULus is listed to the UL standard and the harmonized CSA standard for both the US and Canada. The NEC does not name these standards but requires connectors to be listed and identified for the conductor and the use, which in practice means the right one of these five.
The five standards
| Standard | Covers | Key tests | Marking you will see | Where the NEC requires it |
|---|---|---|---|---|
| UL 486A | Wire connectors for copper conductors: compression and mechanical lugs, splices, terminals | Secureness (pull-out), heat cycling 500 cycles at 100 C with resistance limits, static heating, torque for mechanical | 486A, or 486A/B when dual-rated; CU, CU9 for 90 C | 110.14 terminals identified for the conductor; 110.14(D) torque |
| UL 486B | Wire connectors for aluminum conductors | Same as 486A plus current-cycling with aluminum's oxide and creep behaviour; oxide inhibitor evaluated | 486B, AL, AL7CU or AL9CU when dual-rated | 110.14(A) aluminum must be terminated in connectors identified for aluminum |
| UL 486C | Splicing connectors: insulated multi-taps, in-line splices, twist-on connectors | 486A/B tests plus dielectric withstand on the insulation and pull on the splice | 486C, with voltage rating and conductor range | 110.14(B) splices made with devices identified for the use |
| UL 467 | Grounding and bonding equipment: ground rods, rod clamps, pipe clamps, bonding jumpers, compression grounding connectors, ground bars | Fault-current test, corrosion, direct-burial exposure, mechanical strength of clamps | 467, plus Direct Burial or DB where evaluated for it | 250.8 listed connectors for grounding; 250.70 direct burial where buried; 250.64(C) irreversible compression for buried GEC splices |
| UL 6703 | Connectors for use in photovoltaic systems: MC4 and equivalents, branch connectors, in-line fuses | 1000 V or 1500 V DC dielectric, UV and temperature cycling, IP rating, intermateability declared by the listee | 6703, voltage 1000 V or 1500 V DC, current, IP67 or IP68 | 690.33 connectors listed and, where mated, listed as intermateable |
What the tests prove, and what they do not
The 486 series is a performance standard for the electrical joint. The heat-cycling test runs current through a terminated sample for hundreds of cycles and rejects any connector whose resistance drifts; that is the test that separates a lug that stays cool for thirty years from one that cooks a breaker. It does not evaluate the conductor class unless the listing says so: a lug listed for Class B stranding has not been tested on fine-strand welding cable, which is why long-barrel lugs carry a separate flex listing.
UL 467 is about the grounding path surviving a fault and the environment. A clamp listed to 467 has carried a fault current without loosening and has been exposed to corrosion; a clamp additionally marked Direct Burial has been evaluated for continuous soil contact. A 467 clamp without the DB marking is legal above grade and not below it.
UL 6703 adds the outdoor and DC dimensions: dielectric strength at the rated DC voltage, UV exposure, and thermal cycling, and it requires the listee to state which other connectors theirs may be mated with. That last part is what NEC 690.33(C) enforces, and why mixing MC4-style connectors from two manufacturers is a violation even when they click together.
Reading a marking
- cULus: listed by UL to the UL standard and the CSA harmonized standard; valid in the US and Canada. UL alone: US only. cUL: Canada only.
- AL9CU: listed for aluminum and copper at 90 C. AL7CU: 75 C. CU: copper only.
- 486A/B on one lug means dual-rated under both standards.
- DB or Direct Burial on a 467 connector: buried use permitted.
- A die index and color on a compression lug come from the 486 listing and identify the crimp that was tested; see the die chart.
Which listing does the job need?
| Job | Listing required |
|---|---|
| Copper feeder to a breaker or lug | 486A, torque per marking |
| Aluminum service entrance conductor | 486B, AL9CU or AL7CU, oxide inhibitor |
| Splicing two feeders in a gutter | 486C insulated multi-tap, or 486A compression splice with listed insulation |
| Ground rod clamp, rod covered by soil | 467 with Direct Burial marking |
| Grounding electrode conductor splice below grade | 467 irreversible compression or exothermic; mechanical not permitted |
| Bonding jumper to a water pipe | 467 pipe clamp |
| MC4 connector or branch on a 1500 V string | 6703 at 1500 V DC, intermateable with the module connector |
| Battery cable lug on a 48 V lithium bank | 486A, flex-rated long barrel for fine-strand cable |
Quick answers
Is a UL 486A lug acceptable on aluminum wire? No. Aluminum requires 486B; a dual-rated 486A/B lug marked AL9CU or AL7CU covers both.
Does UL 467 mean the clamp can be buried? Only if it is also marked Direct Burial or DB. Plain 467 is for above-grade use.
Can two brands of MC4 connectors be mated if both are UL 6703? Only if one manufacturer's 6703 listing names the other as intermateable. Otherwise NEC 690.33(C) prohibits it.
What does cULus mean on a lug? Listed for the United States and Canada under the harmonized UL and CSA standard.
Every Conversions Tech lug, splice, grounding connector and PV connector carries the listing in this table for its use, with the file number available on request. Compression lugs · mechanical lugs · grounding connectors · UL 6703 MC4.
