Maintenance Technology July 2017 - 33

ELECTROMECHANICAL RELIABILITY

Specified tests
In defining and quantifying the "sealedness" levels
of the three ingress protection categories, i.e.,
"sealedness" against body parts, solids and liquids,
the IEC Standard 60529 prescribes corresponding
tests. General test requirements recommend the
atmospheric conditions during which each test
should take place, while specific test procedures
stipulate the following:
■ location of the contaminant source as compared
to the electrical equipment
■ length of time that the electrical equipment
should be subjected to the contaminant
■ amount of contaminant to which the electrical
equipment should be subjected.

Interpret the IP
Code Correctly
PLANT PERSONNEL often see the terms "sealed," "waterproof," and "dust
tight" in marketing and technical literature for electrical equipment. In
dusty or wet applications, such as industrial slurry manufacturing, offshore
oil rigs, water/wastewater treatment facilities, and milling/hulling processes,
the level of "sealedness" is of prime importance to avoid contamination. But
what do these terms really mean and is there a way to precisely quantify that
"sealedness?" 
The answer is yes, according to Meredith Christman of IMI Sensors,
a division of PCB Piezotronics (pcb.com, Depew, NY). In fact, an international standard that helps personnel do just that has been in place for
almost 40 years.
In a recently posted white paper, Christman cites the International
Electrotechnical Commission's IEC Standard 60529: Degrees of Protection
Provided by Enclosures that, in 1976, introduced the concept of quantifying
a product's level of "sealedness" with the establishment of the Ingress
Protection (IP) Code. Limited to enclosures for electrical equipment with a
rated voltage of less than or equal to 72.5 kV, this standard defines protection against ingress of body parts, solids, and liquids toward hazardous
electrical or mechanical components.
Christman then goes on to explain how plant personnel can interpret the
IP Code. Among other things, she includes details on:

Meredith Christman is a product manager II with IMI Sensors, a
division of PCB Piezotronics, Depew, NY, pcb.com.
JULY 2017

Specific IP ratings
Once a product has successfully passed the appropriate tests, it can be marketed with a specific
IP rating. This rating consists of the IP designation
followed by one of four alphanumeric characters,
with each character identifying a particular level of
protection or a specific nuance about a particular
protection level.
■ Alphanumeric #1: Protection against ingress of
body parts and solids (with priority to solids). 
Ratings range from no protection to protection
against solids as fine as dust. When a product
is rated to a particular level, it can be automatically assumed that that product could also be
successfully rated to all other levels below it.
Performing the tests associated with the lower
levels of protection is not required.
■ Alphanumeric #2: Protection against ingress
of liquids. Ratings range from no protection
to protection against any liquid during a
continuous-submersion application. When a
product is rated to a particular splash level, it
can be automatically assumed that that product
could also be successfully rated to all other levels
below it. However, when a product is rated to
a particular submersion level, it can only be automatically assumed that the product could also be
successfully rated to the other submersion levels
below it without additional testing, but not to the
lower splash levels. If a product needs to have
both a splash and submersion rating, then both
sets of applicable tests need to be performed.
■ Alphanumeric #3: Protection against ingress
of body parts if not adequately described in
alphanumeric #2.
■ Alphanumeric #4: Supplementary information.
For more details, download the white paper,
"Keeping Out Contaminants: Understanding
Ingress Protection Ratings" by going to https://pcb.
com/Resources/White-Papers and clicking on the
"Industrial" tab. MT

-Jane Alexander, Managing Editor
MAINTENANCETECHNOLOGY.COM | 33
http://www.pcb.com https://pcb.com/Resources/White-Papers http://www.pcb.com http://www.MAINTENANCETECHNOLOGY.COM
Table of Contents for the Digital Edition of Maintenance Technology July 2017
