MDP distance to Generator

[rajuncajun75]

To all,

I am looking to find or see if there is a specific code in the NFPA for a distance stated for a MDP to a generator, or is it something the AHJ determines?

I am currently in Somalia contracting with the military. The entire base is run on many generators. The Military is now looking to buy several big generators and install MDP's and transfer switches along the Hesco wall behind the new generators for this site to upgrade the electrical system.

I dont recall any code reference for a distance of a MDP to a diesel generator...whether it be in Article 445 or in Section 500. I have also looked under NFPA 37 and 110. I have seen a recommendation of about 60-90 feet...but that seems a bit far given our military installation is not that big.

Any insight is appreciated

 

[tom baker]

section 110.26

 

[don_resqcapt19]

If the generator has an OCPD and the conductors originate at the load side of the OCPD, those conductors are feeder conductors and there is no limit on the length of those conductors.

If there is no OCPD at the generator, then the maximum length is determined by one of the tap rules in 240.21(B). If the generator is outside and he MDP is outside, or inside nearest the entry of the of the conductors, that length is also unlimited. Otherwise you would pretty much be limited to 25'.

Note, that not everyone agrees that 240.21(B) applies to generator conductors as there is a rule in 240.21(G) for generator conductors.

 

[tom baker]

Sorry I answered early this AM, to me distance was clearance between them not the vd distance