1 Megohm or less?

[jscottelwood]

I am preparing for my upcoming Prometric exams, 2A and 2B
(Electrical General and Electrical 1 & 2 Family Dwellings)

I am going through my code book and highlighting as I read it.

On page 70-406 of NEC 2005.

Article 516.10(A)(4)(1)...states" to ensure that the parts being coated are electrically connected to ground with a resistance of 1 megohm or less"

That sure sounds like a lot of resistance for electrostatic coating!

Anyone?

 

[bphgravity]

Not really. Most of the requirements in 516 come from the NFPA 33.

In most all static discharge applications, 1 million ohms is all that is needed.

 

[jdsmith]

I don't have my copy of the NEC handy, but is this referring to the resistance from an ESD-safe working area to ground? The regulations around ESD-safe tools, workbenches, storage cabinets, etc, call for a resistance to ground between 10^6 and 10^9 ohms. Less than 1 megohm can be bad because any charge that has built up dissipates too quickly, resulting in too much current flow through the device, which kills it.

 

[LarryFine]

Less than 1 megohm can be bad because any charge that has built up dissipates too quickly, resulting in too much current flow through the device, which kills it.

The same can be said for technicians. :wink: