How deep can an IP68 protective case go?

Answer: Only as deep as the agreed figure. The standard sets no default; 1.5 m is common, while 3 m or 10 m units are tested case by case.

Can a digit 7 report stand in for digit 8?

Answer: No. Seven is a fixed 1 m for 30 minutes, eight is agreed, and the methods and verdict clauses differ.

Does a longer soak mean a stricter verdict?

Answer: The verdict stays the same, no water inside, but longer runs expose compression set and lid creep. Above eight hours, re-measure squeeze.

What if only condensation appears?

Answer: Split the areas. Condensation on a non-sealing surface touching no electrics may pass; condensation on a seal face counts as ingress.

Can the sample size be reduced?

Answer: Three units for type testing and five for lot immersion is the usual floor. A buyer may tighten it; a supplier may not.

IP68 Protective Case Acceptance: Test Items and Pass Criteria

Quick answer: IP68 carries no default depth. An IP68 protective case is accepted against numbers in the order — depth, duration, water temperature — then verified by one immersion run and a positional check after opening.

Where the IP68 Protective Case Rating Ends
Writing the Continuous Immersion Conditions
How a Long Soak Breaks the Seal
What to Inspect After Opening
Lot Decisions and Report Contents
FAQ

1. Where the IP68 Protective Case Rating Ends

Digit 8 in IEC 60529 means continuous immersion, and the standard leaves depth and time to the buyer and the maker. No default exists, so one code can cover 1.5 m for 30 minutes and 3 m for 2 hours.

The IPX7 boundary comes first. IPX7 is closed: 1 m to the base, 150 mm over the top, 30 minutes. IPX8 is open, usually from 1.5 m upward. An IP68 protective case printed without numbers measures nothing.

Item	IPX7	IPX8
Depth	1 m at base, 150 mm over top	Agreed, commonly from 1.5 m
Duration	Fixed 30 minutes	Agreed, 30 minutes to 24 hours
Static head	About 10 kPa	About 15 kPa at 1.5 m
Verdict	No harmful ingress	Clause by clause

2. Writing the Continuous Immersion Conditions

Five numbers make the run repeatable: 1.5 m to the base, 150 mm of water over the top, 30 minutes plus or minus one, water at 20 degrees Celsius plus or minus five, and no more than 3 K between water and specimen.

IP68 protective case: olive green closed case angled on a soft green backdrop, folding handle centred on the front, three lid ribs

A 1.5 m column is about 15 kPa, which over a 600 by 400 mm lid comes to roughly 3600 N. Agree a centre deflection limit of 0.3 mm, or the gasket is pulled open.

Vent first, with the equalising valve cracking at 3 kPa. Trapped pressure cancels the opening minutes of load, and a vacuum pulls water in at touchdown.

3. How a Long Soak Breaks the Seal

Thirty minutes can pass where eight hours fail. Four mechanisms work while the pressure sits.

Compression set comes first. An 8 mm cord in a 6.2 mm groove gives 1.8 mm of squeeze. Held at 70 degrees Celsius for 24 hours, a compound setting more than 20 percent is not built for long soaks; eight hours costs about 0.2 mm.

Lid creep comes second: at 15 kPa a flat lid keeps moving, and the centre travels from 0.3 mm to 0.5 mm in a day. Thermal breathing between 50 and 15 degrees pumps the shell like a bellows. A 0.2 mm grain of sand holds a gap open at 15 kPa.

4. What to Inspect After Opening

The inspection needs an order and a number, or two people will reach two verdicts on one IP68 protective case. Dry it, open the lid, read the walls, the seal face, then the valve seat.

IP68 protective case: olive green closed case flat on a pale grey sweep, two latches along the front rim, folding handle on the right face

Location	Finding	Verdict
Inner walls and corners	Droplets, pooled water	Any droplet fails
Seal face	Continuous film	Film joining two areas fails
Latch pockets and hinge pin	Seep marks, white stress lines	Fail
Lid centre	Permanent set over 0.3 mm	Fail as structural
Whole case	Weight gain over 2 g	Retest

Weighing is worth its own line: a 2 g gain is about 2 ml of water.

A lid centre that stays 0.3 mm low has yielded. White stress lines in a latch pocket mean the gasket there has lost its squeeze.

5. Lot Decisions and Report Contents

Type testing runs three units through the full scope. Routine sampling runs five per lot through immersion; one failure doubles the sample to ten, and a second returns the lot.

Dispute	Usual claim	Ruling
Code printed, no report	The rating is enough	Depth, duration and report number required
IPX7 report offered	It is all water	Rejected; digit 8 is tested separately
Case went in unvented	Habit	Condition not met, rerun
New gasket supplier	Old report reused	Structural change, retest

An IP68 protective case report carries the standard and its year, agreed depth and duration, specimen numbers, temperatures and photographs. No averaging: one leak in three fails the batch.

Conclusion

Acceptance turns an open-ended code into measurable limits: depth, duration, temperature, lid deflection and a checklist read after opening. Fix the items and the verdicts, and one IP68 protective case reads the same across shifts, labs and lots.

This article discusses only the container (case body) side of specifications and design intent, and does not cover any handling, loading or use of the contents.