Rainproof (IP65) vs Waterproof (IP67): 3-Year Field Data

“Rainproof” is not a standard — it is a trade term that maps to IP65. When a buyer asks for a “rainproof power supply,” they almost always need IEC 60529 IP65: water jets from a 6.3 mm nozzle at 12.5 L/min and 30 kPa, from 3 metres, for 3 minutes. Getting that mapping right up front saves a round of RFQ confusion.

The more useful question is whether you need IP65 or IP67. Here is three years of return data to help decide.

What Field Returns Actually Show

Aggregated return rates by installation type, 36-month window:

Two readings stand out.

On a drained vertical facade, IP65 and IP67 are within 0.2 percentage points of each other. The 30% premium buys essentially nothing there. This is the most common overspend in outdoor signage.

In coastal installations, IP65 fails nearly four times as often as IP67 — 4.2% versus 1.1%. That is where the premium pays.

The Coastal Story Has a Twist

Here is the counter-intuitive part. When we broke the coastal failures down by root cause:

Nearly half of coastal failures are terminal oxidation, not water getting inside the housing. Salt-laden air attacks tin-plated contacts from outside, at the connector interface, regardless of the enclosure rating.

Which means: in a coastal installation, upgrading from IP65 to IP67 addresses roughly half your problem. The other half is solved by:

• Gold-plated terminals instead of tin — adds well under $1 per unit
• Conformal coating on the connector area — 3–6% of unit cost
• Dielectric grease in the connector at install — a few cents

Combined, those three cost under a fifth of the IP65→IP67 upgrade and address the larger share of the failure mode. The right answer for a coastal job is usually IP67 plus coated connectors, not IP67 alone.

Where IP65 Is Genuinely Enough

Specify IP65 when all of these hold:

• Mounted vertically or under a soffit
• Water drains away; no pooling around the housing
• No pressure washing
• Further than 2 km from salt water
• Cable enters from below (drip loop)

That covers the majority of building-mounted signage. Our CFX IP65 signage series runs 150 W to 500 W for exactly this set of conditions.

Where IP67 Is Not Optional

Specify IP67 when any of these hold:

• The unit can be submerged temporarily — planter boxes, low cabinets, flood-prone sites
• Water can pool around the housing
• Within 2 km of the coast
• Pressure washing at close range
• Buried or semi-buried enclosures

Our R series IP67 covers 60 W to 350 W. Where no earth ground is available, the LP Class II series is the correct choice — Class II construction means double insulation with no reliance on a protective earth.

The Cost Breakdown

Going from IP65 to IP67 adds roughly 30% to unit cost, split as:

Note that 35% of the premium is potting, which brings the thermal penalty with it — a potted unit’s internal hotspot runs 8–12°C hotter than a vented one, and every 10°C halves capacitor life. In a hot climate with a drained installation, that trade is actively negative.

Decision Tree

Two Further Misconceptions

1. “IP67 units last longer because they are better built.” Not necessarily. In a hot, drained, unventilated installation, the potting that delivers IP67 also raises internal temperature, and the IP65 unit can outlive it. Match the rating to the water exposure, not to a general sense of quality.
2. “The cable is as waterproof as the housing.” The rating applies to the enclosure as tested, typically with a specified cable diameter in the gland. Fit a thinner cable and you have changed the seal. Always specify cable OD in the RFQ.

For the full rating comparison including IP44, see IP44 vs IP65 vs IP67. For the specification detail behind the failure modes, see 7 specs that decide lifespan.

Tell us the mounting position and distance from shore — we will recommend the rating, and tell you when IP65 is the better buy. → Request a quote · Browse by IP rating