Editing Electrical connector (section)

===Failure modes===

The majority of connector failures result in intermittent connections or open contacts:<ref name="navy">{{cite web |url=https://www.navsea.navy.mil/Portals/103/Documents/NSWC_Crane/SD-18/PDFs/Products/Connectors/ConnectorsFailure.pdf |title=Connectors: Failure Mechanisms and Anomalies |access-date=1 July 2019 |website=Naval Sea Systems Command}}</ref><ref>Normalized failure mode distributions were originally compiled from a combination of: MIL-HDBK-978, “NASA Parts Application Handbook”, 1991; MIL-HDBK-338, “Electronic Reliability Design Handbook”, 1994; “Reliability Toolkit: Commercial Practices Edition", Reliability Analysis Center (RAC), 1998; and “Failure Mode, Effects, and Criticality Analysis (FMECA)”, RAC, 1993.</ref>

{| class="wikitable"
|-
! Failure mode
! Relative probability
|-
| Open circuit || 61%
|-
| Poor contact || 23%
|-
| Short circuit || 16%
|}

Connectors are purely [[Passivity (engineering)|passive]] components{{snd}}that is, they do not enhance the function of a circuit{{snd}}so connectors should affect the function of a circuit as little as possible. Insecure mounting of connectors (primarily chassis-mounted) can contribute significantly to the risk of failure, especially when subjected to extreme shock or vibration.<ref name="navy" /> Other causes of failure are connectors inadequately rated for the applied current and voltage, connectors with inadequate ingress protection, and threaded [[#Backshells|backshells]] that are worn or damaged.

High temperatures can also cause failure in connectors, resulting in an "avalanche" of failures{{snd}}ambient temperature increases, leading to a decrease in insulation resistance and increase in conductor resistance; this increase generates more heat, and the cycle repeats.<ref name="navy" />

[[Fretting]] (so-called ''dynamic corrosion'') is a common [[failure mode]] in electrical connectors that have not been specifically designed to prevent it, especially in those that are frequently mated and de-mated.<ref>{{cite web |publisher=[[TE Connectivity]] |url=http://dlnmh9ip6v2uc.cloudfront.net/datasheets/Robotics/ENG_CS_82012_Ribbon_Cable_Interconnect_Sol_0412.pdf |title=Ribbon Cable Interconnect Solutions |page=30 |date=April 2012 |access-date=1 July 2019 |quote=By its design the traditional failure mode in tin plated connections, fretting corrosion, is prevented}}.</ref> Surface [[corrosion]] is a risk for many metal parts in connectors, and can cause contacts to form a thin surface layer that increases resistance, thus contributing to heat buildup and intermittent connections.<ref name="reliability">{{cite web |url=http://ieee-holm.org/h2004/h2004antler.pdf |title=A Perspective on Connector Reliability |last1=Mroczkowski |first1=Dr. Robert S. |publisher=connNtext |website=IEEE |access-date=1 July 2019 |date=15 October 2004 |archive-date=25 October 2021 |archive-url=https://web.archive.org/web/20211025000712/https://ieee-holm.org/h2004/h2004antler.pdf |url-status=dead }}</ref> However, remating or reseating a connector can alleviate the issue of surface corrosion, since each cycle scrapes a microscopic layer off the surface of the contact(s), exposing a fresh, unoxidised surface.