Undersized EGC?

[frequency]

Hello all,
First of all, I highly respect everyone here and appreciate all your feedback.
My question is, I am pulling wire for a range which is being protected by a 40 amp OCPD. I am installing #8awg ungrounded and grounded phase conductors. Now i am being told that #12awg is ok to use as an EGC? The raceway system consists of ENT in the concrete slab with RMC risers to each point. According to table 250.122 the minimuk size EGC is #10awg. Am i missing something here? Also, what are the possible causes due to an undersized EGC? Thank you all for your time.

 

[augie47]

Whomever is advising you that a #12 is a sufficient EGC is the person "missing something".
Table 250.122 shows that circuits over 30 amps and not exceeding 60 require a #10 grounding conductor.
This size is based on the ability of the conductor to provide a sufficient low impedance path in the event of a ground fault.

 

[frequency]

That's what I thought myself, Thank you Augie clarify this.