On Tue, 06 Jan 2009 01:01:27 -0700, you wrote:

>Xiaofan Chen wrote:
>> This will depend on the device and the standards applied.
>> Different standards will have different requirement.
>>   
>I've dug some more online as well, and it really seems that all of them 
>hover in the 5mm or larger category.
>
>Considering the pitch of the terminal block that I was planning on using 
>is less than 5mm, the answer I finally have come up with is really in 
>the "not the type of answer I was looking for" category:  That is:  "If 
>the customer wants to hook 120V to this they can just use an external 
>relay, so I don't have to deal with it.".
>
>Which is what I really felt was the correct thing to do in any 
>regards... but was trying to make a few customers who had asked for 
>120/240V capable relays onboard happy.
>
>-forrest

You also need to consider what the clearance is between - standards typically state different
figures for safety clearances  versus between live parts. The former would cover seperation between
live parts and low-voltage areas, and across safety components like fuses. It is generallly not
practical to use the same clearences for non-safety clearances - e.g. across triacs, relay contacts
etc.
 
ISTR that for 230v it's typically about 5mm for safety clearences to count as 'reinforced/double
insulation' unless it's an environment subject to heavy dust etc.contamination.

Clearance requirements can sometimes be reduced by conformal coating.  

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