This is a discussion I have had with our designers when we should be using thermal reliefs for connections to ground planes. For low current it is a "don't care" but when we get into high current (>10A) the spokes should get larger and will essentially become no thermal relief. We use PADS PowerPCB and I believe it can handle the changes. Just getting folks to do it. (it is extra work... sigh) But this is just my opinion, Phil -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of grandrien Sent: Monday, November 25, 2013 3:28 PM To: [log in to unmask] Subject: Re: [TN] PWB/PCB, clearance ring Hi, We use same clearance from pad outline whatever the hole diameter in middle. I don't see the reason for different values. Main reason for the copper clearance is the copper etching precision for pcb mfg, electrical isulation for PCBA reliability or assembly. Rgds ======================================== Message du 25/11/13 15:39 De : "Victor Hernandez" A : [log in to unmask] Copie à : Objet : [TN] PWB/PCB, clearance ring Fellow TechNetters: Are all PWB/PCB internal clearance rings the same diameter or do the clearance ring diameter vary by drill hole size? How is the clearance ring diameter selected? Victor, ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ ___________________________________________________________ Shopping Noël : Des idées cadeaux au juste prix à voir sur Voila.fr http://shopping.voila.fr/vitrine/jouets/p_7/prods_9 ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________