Hole Ring Thickness

Im confused on how to choose the correct ring thickness. Here are 2 examples of relays that both have 1.3mm holes. The ring thickness is substantially different. Obviously he larger relay has a higher current rating. Which should the ring thickness be on a 1.3mm hole?

Choosing based on graphic display is not a wise approach. Graphic items most always look much larger than they physically are. Folks talk about dimensions of 0.1mm as if knowledgeable and fail to realize the average thickness of a Human hair is 0.15mm (photo).

A wise approach is to consider:
• Is board made by a PCB company, at home by CNC, Etching, Transfer
• How much current/voltage can the Relay handle and how much your design requires
• Copper layer thickness… etc.

Big contact pads will seldom ever, (if ever) be too big to cause a problem but, small pads can be a problem.

Hole size: Many relays have small diameter contact pins, some have wide blade contacts. It’s best to use the smallest diameter that accepts the contact so as to reduce solder bridging and leakage through hole.

I made my own Relay parts to reflect the above considerations and shown below.

hair copy

I have had boards made with the Omron G5LE part in Fritzing. I am unsure how to determine the hole size or ring thickness, but the part fit fine. I intent to make a board with an Omron G5Q, but just looking at the graphic the ring thickness looks quite narrow. The G5Q has pin 1.3mm ± 0.1mm. I intend to use 1.5mm holes. What should the ring thickness be? The relay is rated at 5a.

Make the Ring large but, not so large as to touch the other contacts or extend much beyond the relay’s perimeter. See the Gap on mine? That gap is about the thickness of a piece of paper. The reality of it is, they are fairly small for a large part and you’re not making a digital wrist-watch…

I could suggest a dimension but, prefer you/user do the homework…

image below shows HUE relay on actual PCB.

Usually you use the footprint size from the datasheet for that part, but like Opera says, bigger will make it stronger. In some cases you use an oval, like Opera’s pic, to make it even stronger.