401(k) deferrals and SEP contributions in same year?

[Guest C.R. Gravitt]

Can an employee/shareholder (don't know percentage) of a C-corp contribute to a 401(k) plan and make a SEP contribution based on Schedule C income from a side business? If it makes a difference, the employee did not max out their deferral to the 401(k). What would you use as the limit - would you have to net out the 401(k) deferral from the total amount eligible for the SEP? Any help is appreciated!

[Guest TracyAndrews]

I have the same, or at least similar, question posted under the SEP Section, I'm getting a lot of pressure before 4/15 deadline whether an employer can make a contribution to his existing SEP Plan, although he has adopted a new 401(k)Plan. He does not have to cover his new employees under the SEP (3 out of 5 year rule) even though they participate in the 401(k). Is this right???