IP and IK Ratings: What They Do and Do Not Cover

What an IP code actually certifies

The code has two digits and is defined by IEC 60529. The first digit, from 1 to 6, covers solids and the second, from 1 to 8, covers liquid. The solid scale runs from 50 mm objects up to a dust-tight enclosure at 6; the liquid scale runs from vertical dripping at 1 through spraying and jetting to immersion at 7 and 8. So IP65 is dust-tight and protected against water projected by a nozzle from any direction, IP66 is dust-tight and protected against powerful jets, and IP67 is dust-tight and able to survive a defined period of temporary immersion. Two consequences follow. A rating is a test result on a specific sample, not a property of a design idea, so the report names the model, the orientation and the test conditions. And the digits describe exclusion, not internal conditions: an enclosure can be IP68 and still be full of condensation on the inside.

IP65, IP66 and IP67: the differences that matter

For a road luminaire, IP65 or IP66 is the usual requirement, with the higher figure justified where the installation is exposed to driving rain and road spray at speed. IP67 appears more often on battery compartments, buried junction boxes and connectors than on the optical chamber. The trap is that IP67 and above usually means a sealed volume, and sealed volumes move air when they heat and cool. Without a breather or a pressure-equalising membrane, a luminaire that warms during the day and cools at night draws moist air in through the cable gland; the water arrives as vapour, condenses on the optics, and no amount of water-jet protection prevents it. That is why an ingress rating should be paired in the specification with a requirement for pressure equalisation, a defined cable gland type, and a design that avoids sealing a cavity with a large daily temperature swing.

Why one luminaire is not one IP rating

A solar street light contains at least three separate enclosures: the optical chamber with its LED board, the driver and controller cavity, and the battery compartment, which may sit inside the luminaire, in a box on the pole or in a chamber underground. Each has its own sealing problem. The battery compartment fails most often, because it combines the largest internal air volume, the largest thermal swing and, if it is buried, the possibility of standing water. The specification should therefore carry an ingress requirement per compartment rather than a single headline figure for “the light”, and it should state the orientation the test applies to. Where a luminaire is offered in versions that share a housing but differ in driver and battery, the report must cover the version being supplied.

IK impact ratings: IK08, IK09 and IK10

Impact resistance is defined by IEC 62262 and expressed on the IK scale from IK00 to IK10. The middle of the scale is where most outdoor luminaires sit: IK08 corresponds to an impact energy of 5 joules, IK09 to 10 joules and IK10 to 20 joules, delivered by a defined striker against defined points on the enclosure. For context, 5 joules is a solid knock and 20 joules is heavy. The choice should follow the exposure: a luminaire at a bus shelter or sports court where balls and trolleys reach it wants more than one on a tall pole above a footpath. Impact and ingress interact, because a cracked diffuser destroys the ingress protection in one moment, so the requirement should name the impact rating of the diffuser or cover as well as the housing. Where vandalism is a known risk, the more useful measures are mounting height, tamper-resistant fasteners and an unobtrusive shape.

What IP and IK do not cover

Neither rating is a durability statement and neither touches the electrical side of the product. IP and IK say nothing about surge immunity, which for a pole-mounted luminaire in a thunderstorm-prone area is often the failure that ends its life; that belongs with a surge protection requirement, with devices tested to IEC 61643-11 where an external protector is fitted, and with a stated immunity level for the driver and controller. They say nothing about UV stability, salt-spray corrosion, thermal management or gasket material quality. They say nothing about whether the enclosure will still seal after three years of baking and freezing, because the test is performed on a new sample. Nor do they say anything about the pole, whose galvanizing is assessed against a coating standard such as ISO 1461 with a measured thickness or mass, and whose structural design follows a framework such as EN 40. Three rules make the clauses enforceable: write the requirement per compartment and name the standard, require the test report to identify the exact model offered, and add sealing, gland and breather checks to the pre-shipment inspection listed in the inspection checklist and tender specification.

How we can help

We are a China-based trading and project sourcing company, not a manufacturer. We review specifications and BOQs, match a product and configuration to your site conditions, source from qualified manufacturers, and manage quality through to pre-shipment inspection.

• Turn a vague “weatherproof” clause into per-compartment IP and IK requirements with standards named.
• Ask the supplier to obtain test reports that identify the exact model and version you are buying.
• Add sealing, gland and breather checks to the pre-shipment inspection list.
• Keep surge protection, coating and structural standards in the same section of the specification.

If you are preparing a tender or specification and want a second opinion, contact us.