Class 2 vs Class II vs LPS vs SELV: What Each Label Actually Means

“Class 2” and “Class II” are not the same thing written two ways. One is a North American output power limit defined in UL 1310; the other is an insulation construction defined in IEC 61140. A power supply can be one, the other, both, or neither. Whether your electrical inspector signs off the job can come down to a Roman numeral versus an Arabic one on a label.

Here is what each of the four labels actually governs.

The Four, Defined

Class 2 — A Power Limit (UL 1310)

Class 2 is about how much energy the output can deliver, on the theory that below a certain threshold the circuit cannot start a fire or deliver a harmful shock. The limits are:

• ≤ 60 V DC or ≤ 42.4 V peak (30 V RMS) AC
• ≤ 100 VA output
• Current limited per the tables in UL 1310 (for a 24 V output, roughly ≤ 5 A before the inherent limit, and ≤ 8 A with overcurrent protection)

Why buyers care: NEC Article 725 permits Class 2 wiring to run without conduit, using cheaper cable and simpler methods. On a large installation that saving is worth more than the driver price difference. This is the actual commercial reason “Class 2” appears in so many North American specs.

Note the geographic trap: a cUL mark means the product was evaluated to Canadian standards (CSA C22.2). cULus means both US and Canada. A unit marked only cUL does not carry a US listing, and reading “cUL listed class 2” as US coverage is a common and expensive mistake.

Class II — An Insulation Construction (IEC)

Class II says nothing about output power. It says the product achieves safety through double or reinforced insulation rather than through a protective earth connection. That is why Class II products have no earth terminal — the symbol is a square inside a square.

Class II is the right construction where:

• No reliable earth is available at the installation point
• The installation is outdoors and earth bonding is impractical
• The luminaire is a portable or hand-reachable product

Our LP Class II IP67 series is built this way: 20 W, 36 W, 60 W, 100 W and 150 W at 12 V / 24 V, IP67, no earth required.

LPS — A Source Limit (IEC 62368-1)

LPS (Limited Power Source) comes from the IT and AV equipment standard IEC 62368-1, which has largely replaced IEC 60950 and IEC 60065. It defines a source that, under normal and single-fault conditions, cannot deliver more than:

• ≤ 30 V RMS / ≤ 60 V DC
• Power and current limits depending on whether the source is PS1, PS2 or PS3 — PS2 is roughly ≤ 100 W

LPS matters when the power supply feeds equipment covered by IEC 62368-1 — displays, signage players, networked devices. It is not a lighting standard, and it is not a substitute for Class 2.

SELV — A Voltage Limit (IEC 61140)

SELV (Separation Extra-Low Voltage) requires:

• Voltage ≤ 50 V AC or ≤ 120 V DC (ripple-free)
• Separation from mains by at least double or reinforced insulation
• No connection to earth, and no connection to other circuits that are earthed

Two relatives worth knowing: PELV (Protective ELV) is earthed at one point — allowed but no longer SELV. FELV (Functional ELV) meets the voltage limit but not the separation requirement, and must be treated as live.

The Counter-Intuitive Part: You Can Have Any Combination

This is where procurement goes wrong. Work three examples:

So the sentence “we need a Class 2 / Class II power supply” is not a specification. It is two different requirements and you have to say which one you mean. If you are unsure, state the consequence you need: “no conduit per NEC 725” points to Class 2; “no earth available at the luminaire” points to Class II.

How to Verify a Claim

Manufacturers write “Class 2” on labels loosely. Four checks, in order:

1. Get the mark, not the word. A listing mark carries a file number — for UL it looks like E123456. No file number, no listing.
2. Look up the file number in UL’s Product iQ database (or Intertek’s ETL directory). This takes 2 minutes and catches most overclaims.
3. Check the scope. The listing covers a specific model range and specific output ratings. A family listing may cover the 60 W but not the 150 W variant.
4. Check the geography. cUL ≠ UL. cULus = both.

This is the same verification discipline covered in UL 1310 and Class 2 Power Supplies: What B2B Buyers Actually Need to Verify — that article is about how to check the claim; this one is about knowing which claim you need. For the driver-level standard, see What is a Class P LED Driver?.

Standards Reference

Where Each Applies in Practice

• US architectural signage, long cable runs → Class 2 (conduit exemption) + IP rating. See IP44 vs IP65 vs IP67.
• Outdoor luminaire with no earth available → Class II. LP series.
• Signage with an integrated media player → LPS for the player supply, plus the lighting standard for the LED supply — two different rules on one job.
• EU installations → CE marking covers LVD and EMC; Class 2 is a US concept and does not appear. Asking a European supplier for “Class 2” often produces a confused answer.

RFQ Wording That Gets the Right Product

Send the filled block — we will confirm whether your requirement is Class 2, Class II, or both, and supply the file number for lookup. → Class II IP67 series · OEM/ODM capability · Certificates & datasheets