NEMA/NFPA/NEC Standards for Thermal Overload Testing

[Bloozntooz7868]

Quick one for the North American audience:

Are there any standards (NEMA/NFPA/NEC or other) that specify that thermal overloads need to be current injection tested periodically, and/or after replacement?
There are pro's and con's for testing them - pro's are obvious, but the con's are that they may retain some 'thermal memory' (which is really mechanical memory in the fact that the bimetal may not return to the ambient position) - so should they be tested at all?

I am not after the testing method or explanations on how its done, nor Company best practices - that is all clear - it is just specifically about the neccessity, by any governing standards, for testing to be done.

Thanks in advance.

 

[Bloozntooz7868]

Follow up:

I have come across NETA 2015 Standards stating the following:

Sec 7.16.1.1.B.4 Test motor protection devices in accordance with manufacturer’s published data. In the absence of manufacturer’s data, use Section 7.9

and

Sec 7.9.1.11 49R Thermal Replica Relay: 1. Determine time delay at 300 percent of setting. 2. Determine a second point on the operating curve.

So this is calling for injection testing, but where is this complementing any of the other Standards like IEEE etc.?

 

[jraef]

The world is moving toward solid state overload protection for critical equipment (defined as where you would care about calibration and testing). One reason is, there is no thermal memory or drift over time. If you are still using bimetal overloads, you likely don't care about your equipment very much, because the ONLY reason to use them is their lower cost. And even that is not too different from entry level SSOLs now.


"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

 

[Bloozntooz7868]

No argument there, but as there are hundreds of them on this site (and thousands on other sites), and the fact that Manufacturers keep making them, Projects keep installing them, and Standards keep quoting them, then the question still stands.

I did nearly have an epiphany though - a sudden urge to buy Tulips for the Amine Pump motor, and say that I really do care about him despite the wretched choice of starter protection.