clearancecreepagerelay
I'm looking at this 10A, 277VAC relay and wondering if there is sufficient spacing between the low voltage (3.5V, 100mA) and the high voltage(277VAC, 10A). The foot print looks like this:
Are the 5V leads too close to the high voltage leads? Why aren't the high voltage leads on one side and the low voltage leads on the other side? Also, the use case is to be mounted on FR-4 and there will be a fuse before the high voltage goes to the relay.
You're looking for a "contactor" rather than a relay at those current levels. Tyco are a trustworthy brand, see the MAP200. Other places to look are the companies that make MCBs and other industrial automation controls such as Hager, ABB, GE, Moeller, Schneider, Eaton Cutler-Hammer XTCS500M22B etc.
Here is a diagram that should help: -
Picture taken from this document.
Please also note that creepage distances might have to be bigger dependent on your pollution category and your material group. See this document for further info.
There is also this calculator - I have tried it and for 250V AC, the protection distances seem to be right i.e. basic creepage is 2.5mm with 2.5mm for supplementary making a 5mm total for reinforced. Ditto the clearance figures - they add up to 4.0mm for reinforced: -
Best Answer
The biggest clue that the part is OK is the UL Recognized component mark (the backwards-looking "RU" symbol with C and US) on the part.
You will have to make sure that your PCB traces keep the necessary creepages and clearances, but the part itself (and the pinouts) are perfectly acceptable per UL and therefore not a cause for concern.
The pinout logic is most likely a function of the physical construction of the part given the form factor, or it could be to make it pin-compatible with some other vendor.