There’s a number of reasons for that:
- “Power relay” is an ambiguous term
- There are potentially a lot of variables involved, and a solid answer to such questions (unfortunately) means accounting for those details.
- The internet is increasingly polluted with crummy information of specious origin.
Unfortunately I/we can’t offer you an answer of that sort. Per our terms and conditions it’s your responsibility to decide whether or not a given part is suitable for your needs. Most every component manufacturer/distributor is going to have a similar clause in the fine print.
What I/we can do however, is offer guidance and reference to relevant information that would inform your decision. Grab a beverage, this might take a while…
For reference, I’ll be comparing the PC775-1A-12C-X relay you mentioned as your reference and the 1-1414286-0 mentioned by AP as an example of the “maxi” type relay.
As to the question of continuous current carrying capacity, the relevant portions of the respective datasheets are below. Both have to be de-rated with increasing temperature because Physics, but the “maxi” device actually seems to take a substantial lead at elevated temperatures.
That is only one part of a complicated picture however, because most of the wear and tear on a relay’s contacts happens in millisecond-scale time spans as a relay opens and closes. This post explores those ideas in some depth, and has links to resources of a fairly serious nature.
The implication of this is that it’s tough to be really confident about how much stress a relay is experiencing without tools capable of measuring current on those time scales. We can talk about that if you like, but there’s a bit of a learning curve and convent tools for the task are probably going to be in four-figure price tag territory.
Along those lines however, the datasheets do provide some information about internal construction that’s relevant:
What this is saying is that your “power” relay actually has two sets of contacts in parallel, one made of Tungsten (extremely high melting point) and silver alloy (conducts well) while the “maxi” relay in question just uses one set. The question then is “does it matter to you?” Useful information can be found in the service life/endurance ratings:
Both are rated for 100,000 operations, which equates to about 39 operations every single day for 7 years. Your “power” relay’s switched current specs are somewhat higher, particularly on the “make” side and if you’re switching capacitive loads like inverters that are particularly nasty on that end it might be the better choice. But there is a point when “enough” is indeed enough.
It’s a thing to consider. “What would happen when/if…” sorts of questions are a finer point of good design practice. I drove an ‘82 dodge in college that had one white wire in a harness underhood that rendered the thing completely ephing dead when disconnected. No lights, no engine, no power steering, no nuthin’.
I grant you one guess as to which wire decided to have an inside-the-insulation fracture while I was midway through a left turn on a 4-lane intersection in morning rush traffic…
Bottom line, both of the relays in question might adequately serve your needs, but a truly sound and grounded decision would require you to clarify what your needs actually are.
Side note: there are products like the 2297813-2 available from stock that might prove useful for your line of work.
