American Zettler Relay

The Relay I just purchased is described as a 40A relay when fact it is a 30A relay. You might want to change the description. Part #

Hello @p03981

Can you provide any more details on the 30A specification you are suggesting? Looking at the datasheet from American Zettler they are showing this as a 40A.


Unless I’m missing something the two I bought say 30a right on it

The current ratings in the data sheet for this model relay are far more complex than can be practically marked on the relay nousing.

This first section for a pure resistive load section says:
Ratings Resistive load:

  • Max. switched power: 840W or 11,080VA
  • Max. switched current: 40A (Form A)
  • Max. switched voltage: 277VAC, 28VDC

That matches the product page specifications.

However for practical loads the UL/CUR specifications show (bolding mine):
UL, CUR 1 Form A

  • 40A at 277VAC, General Use
  • 28A at 277VAC, General Use, 100k cycles
  • 30A at 28VDC

I’m not sure how that complexity can best be translated to a database derived web page with parametric searching.

I’ve not worked with relays of this power level much in my life, last time may have been the 1970s. Having read quite a few data sheets for them on this forum in the last few years, I’ve come to feel that high power relays are closer to complex semiconductors in their specification and application. (meaning long boring sessions picking through the fine details in a data sheet :frowning: )


Found this out of American Zettler’s catalog.
You would think if it was 40A it would have been printed right on the relay.
I don’t know doesn’t matter to me as much even 28A is enough for my application. I’m just trying to help save them future problems.

Hi p03981,

Thank you very much for your input on this issue. We try to present accurate information in our parametric search to help you identify the best options for your application. Unfortunately, although we try, it’s not always perfect. As PaulHutch indicated, these things are often not cut and dry, and when we are dealing with literally millions of components, spending the time to determine the best value to enter into any particular parametric box is challenging.

In this case, it would seem like we entered the “headline” value that AZ listed at the top of both their datasheet and their product detail page, as seen below:

We do make errors on occasion, so it’s always recommended to check the datasheet before committing to any particular part, but in this case, I’ll lay most of the blame on the vendor’s marketing people rather than on our website parametrics group.

I believe that another component of the issue is that UL has specific requirements for how relays are rated which may differ from what a specific relay manufacturer uses to rate their own relays. Thus, they rate this particular relay as a 40A relay because it can technically handle that under some rather optimistic circumstances, such as that the temperature remains at 20°C, but without specifying the number of cycles it can handle at this load.

UL has very specific and stringent requirements, and I believe, to get the UL stamp on their relays, they must conform to the UL ratings when printing specifications on the relays themselves. Thus the difference between the marketing headline spec and the spec actually printed on the relay itself.

Your point is well taken and brings more weight to the topic of trying to get specifications from all vendors better harmonized, so one can make the better decisions based on the specifications we list in our parametric search.