Not knowing exactly what you are trying to package, the following is suggested.
There are quite a few standards that you might run into e.g.
NEC, NESC, etc that describe what and how your electrical/electronics must be packaged.

Dear Dough,

Thanks for your reply.

I will be Thankful, if you pleae also tell me from where to get NEC or NESC Standards.

Regards,
nkb

NESC & NEC PURPOSES:

Before purchase any reference will be a good idea to understand the scope and purposes of any code or standard.

Be aware that neither the NEC nor the NESC are intended as a design specification or as an instruction manual. The following describe the purpose of each publication:

1)  NESC "practical safeguarding of persons during the installation, operation, or maintenance of electric supply and communication lines and associated equipment".
_{Usually applicable on utilities environment}

2) NEC "practical safeguarding of persons and property from hazards arising from the use of electricity".
_{The NEC (NFPA 70) is more often used on industrial, residential and commercial facilities and covers utilization wiring requirements beyond the service point.}