Garage/shop wiring update

;-)

Thanks! Rich

On Fri, 11 Sep 2009 09:23:43 -0600, the infamous Steve Ackman scrawled the following:

With total corruption in both major parties, who can tell the difference?

The sole ground rod should be at the service entrance panel. Multiple rods can create ground loops.

Multiple rods can give you a better earth ground, but, of course, they ALL have to lead to the one "main" grounding point.

Cheers! Rich

jk wrote in news: snipped-for-privacy@4ax.com:

Actually you shouldn't assume. It's my day job to install and maintain this stuff. Unlike some places it's a restricted trade here so be assured I have the training and experience. There may be some differences in jurisdictions but AFIK the CEC and NEC treat bonding of grounded conductors quite similarily. My incredulity at seeing a design such as this is more from knowing how uneducated people can screw it up than inexperience with this particular panel brand, which is in fact not a common brand here.

I am aware of the differences for treating grounded conductors (see day job statement above) in non service entrance panels vs. service entrance panels.

The question remanins though. What happens to that insulated terminal strip on the left hand side when the green screw is pulled? Previously it was stated that this strip is NOT jumpered to the other neutral strip. Is this incorrect? This one point seems to be where I find the design quite odd.

Still seems silly to put grounding conductors there when there is a grounding strip on the can right beside it..... service entrance panel or not.

This is simple stuff if the hardware is designed the way we make them north of the 49th. GroundING conductors on the metal enclosure. GroundED conductors on an insulated terminal strip - one on each side jumpered together for convenience in routing the conductors. Bonding screw or strap from the 'neutral' strip to the case. Pull the bonding screw out and throw it away if you choose to use a combination panel for non service entrance. Panels without main breakers have no means to join the neutral to ground. Wires go to the same locations regardless if it's service entrance or not, only the bonding screw changes.

Shows you don't get involved with this much.

That's because NOT EVERY PANEL IS AT A SERVICE ENTRANCE.

THis panel is designed so that it can be used as a downstream panel, where the neutral is NOT allowed to be bonded to ground in the panel.

Some do, some don't, and I suspect it is largely a matter of cost.

jk

Probably because most engineers never deal with this.

Probably not, but that will depend on your local code. If it gets treated as a separate service, he (or she) will NOT be happy. If it gets treated as a sub panel from your house service (or wherever) he will require that it be removed.

IF the building is treated as per 250.32 of the NEC (as it should be for a US installation) then

"250.32 Buildings or Structures Supplied by Feeder(s) or Branch Circuit(s) (A) Grounding Electrode Building(s) or structure(s) supplied by feeder(s) or branch circuit(s) shall have a grounding electrode or grounding electrode system installed in accordance with 250.50. The grounding electrode conductor(s) shall be connected in accordance with

Exception: A grounding electrode shall not be required where only a single branch circuit supplies the building or structure and the branch circuit includes an equipment grounding conductor for grounding the conductive non?current-carrying parts of equipment. For the purpose of this section, a multiwire branch circuit shall be considered as a single branch circuit.

(2) Grounded Conductor Where (1) an equipment grounding conductor is not run with the supply to the building or structure, (2) there are no continuous metallic paths bonded to the grounding system in each building or structure involved, and (3) ground-fault protection of equipment has not been installed on the supply side of the feeder(s), the grounded conductor run with the supply to the building or structure shall be connected to the building or structure disconnecting means and to the grounding electrode(s) and shall be used for grounding or bonding of equipment, structures, or frames required to be grounded or bonded. The size of the grounded conductor shall not be smaller than the larger of either of the following: (1) That required by 220.61 (2) That required by 250.122

The short version of this is if you run a ground conductor with your feeder to this panel, You bond it to the local ground, AND the N-G bond in your panel gets removed.

If you do NOT run a ground conductor, then your ground electrode gets bonded your panel ground bus, and your Neutral gets bonded to your panel ground bus.

No, for a single phase (120-240) panel alternating breakers are on alternate source phases. A,B,A,B,A,B going down the panel

jk

Depending on the installation the NEC requires additional ones for separate buildings, in some cases.

When improperly installed.

jk