LSZH vs PVC vs OFNR vs OFNP: Choosing a Patch Cord Jacket for North America and Europe

Material Names and Fire Listings Are Different Things

Buyers see four terms on drawings and quotations, but they answer two different questions:

• What is the jacket made of? PVC (polyvinyl chloride) or LSZH (low smoke zero halogen, also written LS0H, LSOH or LSHF). Plenum cables often use special low-smoke PVC or fluoropolymer compounds.
• Which fire test has the finished cable passed, and where may it be installed? In the United States and Canada this is a listing such as OFNP, OFNR or OFNG, printed on the jacket. In the EU, cable for permanent installation carries a CPR Euroclass such as Dca or Cca.

A cord can be "PVC, OFNR" or "LSZH, OFNR", and an LSZH cord can have no North American listing at all. That is why an RFQ line that says only "LSZH" or only "riser" is incomplete for a project that crosses both markets.

LSZH vs PVC vs OFNR vs OFNP at a Glance

The "N" means nonconductive (no metal) and the "C" means conductive. Most standard fiber patch cords are nonconductive; an armored cord with a steel tube falls in the conductive family. See armored vs standard patch cords for that case.

North America: NEC Article 770 and the Substitution Rule

NFPA 70, the National Electrical Code, covers optical fiber cables in buildings in Article 770. Cables are listed by application, and the code allows a higher listing to replace a lower one, never the reverse:

1. OFNP (plenum) may be used anywhere OFNR, OFNG or OFN is required.
2. OFNR (riser) may be used where OFNG or OFN is required, but not in a plenum.
3. OFNG and OFN (general purpose) are for single-floor runs outside risers and plenums.

Some cables also carry a limited-smoke suffix, for example OFNR-LS or OFN-LS, now also marked ST1 by UL. It means the cable passed smoke limits in the UL 1685 vertical-tray test. It is a smoke property, not a location rating, and an OFNR-LS cord still cannot replace OFNP.

In Canada, the Canadian Electrical Code uses CSA FT ratings. FT6 corresponds to the plenum test and FT4 to the vertical-tray test, so cords sold into both countries are often marked with both, for example "OFNP (UL) FT6". The authority having jurisdiction on each site makes the final call on what is accepted, and some US data center and enterprise specifications require listed cords even inside equipment rooms.

What the North American Flame Tests Measure

The plenum test is the only one of the three that limits smoke for the basic listing, because smoke in an air-handling space spreads through the building's ventilation. That is why OFNP cords cost more: the compounds that pass NFPA 262 are more expensive than standard PVC or LSZH.

Europe and International: What Makes a Jacket LSZH

"LSZH" is a material claim, and in IEC markets it is checked with a group of tests on the jacket compound and the finished cable. The values below are the limits most often written into cable specifications; check the project documents, because some operators set stricter numbers.

PVC fails the halogen tests by design, because chlorine is part of the polymer; that is the main reason European and public-transport projects specify LSZH. Halogen-free smoke is less corrosive to electronics and less toxic, which matters in data centers, tunnels and buildings with many occupants.

For installed cable in the EU, the reaction-to-fire class under the Construction Products Regulation is a separate requirement. Cords with connectors are generally outside CPR scope, but a project can still ask for cords made from cable with a declared Euroclass. Our CPR Euroclass guide explains the classes, the s, d and a codes and how to check a DoP.

Is LSZH Plenum Rated?

Not automatically. A plenum listing comes only from passing NFPA 262 and being listed by a recognized testing laboratory, and it must be printed on the jacket as OFNP (or FT6 in Canada). Many LSZH compounds are designed for the IEC tests above and are not formulated for the Steiner tunnel. Some LSZH cables carry an OFNR or OFNG listing, and a few constructions are listed for both LSZH and plenum use.

The practical rule: in a US or Canadian plenum, ask for OFNP and check the print; if the project also wants halogen-free, ask for both properties on the same line and expect the supplier to confirm which cable construction meets both. Do not accept "LSZH = plenum" or "low smoke = plenum" as an answer.

Which Jacket to Order by Market and Space

Jacket color follows the fiber grade (yellow for OS2, aqua for OM3 and OM4, lime for OM5), not the fire rating. Fire rating is read from the print on the jacket, not from color.

Writing the Jacket on an RFQ Line

Put the material and the listing in separate fields, and say which document you need to see. The lines below show the format; they are an example, not a real order.

Common mistakes are writing "plenum" without checking whether the space really is an air-handling plenum, asking for "LSZH riser" without confirming a listed construction exists, and assuming a cord bought for Europe can be installed in a US riser. The patch cord buying guide covers the other fields on the same line, and our patch cord wholesale and custom patch cord pages list the cord types we quote. Ask for the rating per line; we confirm which jackets and listings are available for each line in the quotation.