topic Re: PA 5000 series grounding? in General Topics

PA 5000 series grounding?

ddaniels — Tue, 16 Apr 2013 15:57:52 GMT

The PA 5000 series hardware reference guide does not show anything about the grounding lug that is present on the PA-5020 AC power firewalls. Is the grounding information the same as the PA-3000 series? 14 AWG, certified Lug crimpted, using a size #8-32 nut and star washer (supplied), torqued to 15 in.-lbs (not overtightened)?

Re: PA 5000 series grounding?

mikand — Tue, 16 Apr 2013 18:40:13 GMT

I can only see a description for this in the PA-5000_Hardware_Guide_RevB.pdf page 19:

CAUTION: For a DC system, use a grounding wire of at least 14 American Wire

Gauge (AWG). The 14 AWG wire should be attached to an agency-approved crimp

connector (Tyco 34120 or certified Lug), crimped with the proper crimping tool and

attached to the protective grounding lug, using a size #8-32 nut and a star washer

(supplied), on the chassis with the other end connected to the building ground.

Torque the nut to 15 in.-lbs. Do not over tighten.

Re: PA 5000 series grounding?

ddaniels — Tue, 16 Apr 2013 18:45:36 GMT

It's strange that the grounding lug is included on the AC model, yet there's no mention of the grounding lug for AC models in the guide.

I also noticed that the guide says that the systems are grounded to the rack ground and the AC requires a ground line.

Re: PA 5000 series grounding?

mikand — Tue, 16 Apr 2013 19:31:06 GMT

Usually the PSU (if AC with grounded outlet) will provide ground earth to the chassis and by that to the internals of the device aswell.

If the rack itself is grounded (which they usually are) this could bring you a groundloop. On the other hand this ground is only for EMI/EMC purposes so it shouldnt matter (and digital ground within the device is filtered to block out any unwanted frequencies which exists on the analog ground (earth) that is digital ground <-> filter <-> analog ground <-> psu <-> ground/earth through power coard).

Re: PA 5000 series grounding?

ddaniels — Tue, 16 Apr 2013 19:38:35 GMT

Is that the same for the PA 3000 series? That hardware guide shows in Table 2 an AC Power Inlet and Power Supply as well as giving specifications for using the Grounding Lug.