The service panel was moved from exterior garage wall to main house wall 13 ft away. A junction box was used to add length to SEC. The junction box is located on garage ceiling. Is this legal, or is it according to code?
Thanks
Is there an OCPD on the outside of the structure or is that in the panel?
The Meterhead is all that is outside.
Sounds like you have more problems then just the junction box. Could you explain what you have from the point of attachment on the outside to the panel? SEU cable?
Is the box bonded to the GES? Generally, a splice is ok when/if done properly.
As RM is alluding to, unless OCP has been added there would be an issue with too much unfused conductor inside the dwelling.
I agree, but the rule is a bit ambiguous as to what might be considered “too much.”
True, but he did say that the panel was moved 13’. In just about every jurisdiction that would be too much. 
It would be hard to qualify 13’ being “as short as practical”.
Put a disconnect outside & run a 4-wire feed to the panel + separate the neutrals & ECG’s then all will be fine.