Grounding Electrode Conductor Termination 1

[buddy91082]

Per NEC 250.70, exothermic or mechanical lugs can be used to terminate grounding conductors to ground rod electrodes.

Any benefit to either method?

Thanks.

 

[stevenal]

Exothermic provides a permanent low resistance connection. Mechanical can be performed more easily, and in wet weather.

 

[dpc]

In addition to stevenal's points - exothermic requires proper molds and also some level of skill and experience using them. Mechanical connectors are probably simpler and more familiar. That said, a properly made exothermic connection is the "gold standard" and commonly used by electric utilities in their substations.

 

[7anoter4]

I agree with dpc: exothermic connection required good training and of quality molds and material. However the permissible cable temperature in mechanical connection case will be only 250-350 oC but in exothermic connection up to 1083 oC what in turn a reduced cross section area will be allowed. See:
IEEE 142/2007 4.3.3 Connecting to electrodes or
BS 7430/2011
Table 5 Earth fault current densities for 1 s duration for earthing conductors with initial conductor temperature of 30 °C.:
welded: 700 oC bolted 250 oC.

 

[7anoter4]

The connector test standard it is IEEE 837/2014.The test fault-current current is based on wire fusing current for all type of connectors.
If the connector passes this test-it is not important which kind of connector-mechanical, bolted or else-at least 90% of fusing current it could be allowed for a up to 4/0 wire. For a conductor of 500 mcm or more only 61% it is permissible.
They are manufacturers of which product withstand the IEEE 837/2014 test.