Grounding cable properties

[BENNET]

is their a reasonable difference in stranded grounding cable other than flexibility?
250 mcm 19 strand vs 250 37 strand ? also tinned vs bare other than corrosion

 

[PEDRO ESCOVILLA]

do they have respetivley differing insulation types ? one (37 strand) is most likely compact conductors ()noticeably smaller in size and they will be shaped differently as well , six sided ?) i have no experience with "tinning"

 

[BENNET]

they are all bare conductors

 

[gndrod]

is their a reasonable difference in stranded grounding cable other than flexibility?
250 mcm 19 strand vs 250 37 strand ? also tinned vs bare other than corrosion

Up to 8 awg size conductors, solid has less resistance than stranded. Rarely have I run across solid bare conductors larger than #2 Cu for grounding or uninsulated continuous tinned coating. What applications would be relevant?

 

[suemarkp]

I always thought that stranded wire had less impedance than solid, and that the finer the stranding the lower the impedance. Maybe it isn't that simple. I would think impedance would matter in lightning strikes or anything else where there is a major pulse/spike. Makes me curious why we don't use flat braids or fine stranded wires for GEC's whereas many seem to favor solid for a GEC. For an EGC, I would see flexibility as perhaps the only advantage to fine strand??

 

[gndrod]

I always thought that stranded wire had less impedance than solid, and that the finer the stranding the lower the impedance. Maybe it isn't that simple. I would think impedance would matter in lightning strikes or anything else where there is a major pulse/spike. Makes me curious why we don't use flat braids or fine stranded wires for GEC's whereas many seem to favor solid for a GEC. For an EGC, I would see flexibility as perhaps the only advantage to fine strand??

My whoops. The comment is for a dc reading. (See NEC Table 8 conductor properties)

 

[WIMaster]

is their a reasonable difference in stranded grounding cable other than flexibility?
250 mcm 19 strand vs 250 37 strand ? also tinned vs bare other than corrosion

Finer strands are supposed to provide lower IMPEDENCE, finer stranding is also used for "compact conductors, heavier strands are more resistant to physical abuse.

The only reason I have seen for tinned conductors is corrosion resistance either from soil or something in the jacket.

 

[DataCenterGuy]

Stranded Ground Conductors

Stranded Ground Conductors

The "Impedance" noted is, in the case of many grounding conductors, more related to something called "skin effect" where high freqencies generated by the fast rise times of pulse currents (Fourier series components) travel along the outsides of the conductors rather than through them. Therefore, the more surface area the better, which stranding provides. But there's also the matter of practicality, in terms of handling, cost and the frequencies of concern. Unless you're dealing with Signal Reference Ground Grids for something like supercomputers (still a matter of debate in the industry as to usefulness), using something like welding cable (very high strand count and surface area) is gross overkill. Stay with standard electrical stranding unless someone with real credentials has specified otherwise. (Lots of "theorists" out there who call for absurd things they're not paying for without justification.)