Isolated equipment grounding conductor

[petersonra]

Is there any proof that these IG systems are still actually needed

Is there any proof they were ever useful, much less needed.

 

[brantmacga]

Since you are heavily involved with building this type of restaurants I'm curious when the jobs are done and POS equipment is installed how much of it even connects directly to the receptacles?

I’ll speak directly of McD’s because that’s what I have the most experience with.

All of their POS terminals use a 120v 3-wire twist lock connected directly to the receptacle. Only the server will connect to a UPS.

There is a data closet at the back of the store that houses the servers, all connected to a UPS.

The self-order kiosks and cash changers are also on IG circuits. A new store might have 30-40 pieces of equipment connected directly to the IG receptacle.

If there is a power outage, all of the terminals go down, but when they reboot, nothing is lost because the servers are holding the order info.

Here’s a pic of a data closet under Constructon…. This one has a 30A IG circuit feeding the PDU. You can see a few 15A IG receps used for things like the backup cellular dialer, and routers that don’t need to be on a UPS. Anything that is networked will be on an IG circuit, except for the BAS.

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[hillbilly1]

I think where it came in, was when conduit was used as the sole equipment ground. Loose locknuts and fittings introduced noise, and was never changed as a design spec now that a majority of customers require an equipment ground to be pulled now.

 

[delaware74b]

Wasn't the requirement for isolated grounds for early coax-based networks and ground-loop noise on the data lines? In theory that requirement went away with cat5/6/7 twisted pair cabling.

 

[infinity]

I’ll speak directly of McD’s because that’s what I have the most experience with.

All of their POS terminals use a 120v 3-wire twist lock connected directly to the receptacle. Only the server will connect to a UPS.

There is a data closet at the back of the store that houses the servers, all connected to a UPS.

The self-order kiosks and cash changers are also on IG circuits. A new store might have 30-40 pieces of equipment connected directly to the IG receptacle.

If there is a power outage, all of the terminals go down, but when they reboot, nothing is lost because the servers are holding the order info.

Here’s a pic of a data closet under Constructon…. This one has a 30A IG circuit feeding the PDU. You can see a few 15A IG receps used for things like the backup cellular dialer, and routers that don’t need to be on a UPS. Anything that is networked will be on an IG circuit, except for the BAS.

There is nothing extraordinary about these racks or the equipment. Stuff like this has been installed for a decade without the need for an IG system. If it makes an engineer warm and fuzzy to see orange IG receptacles so be it but time has proven that this is a waste of money.

 

[JoeStillman]

Since you are heavily involved with building this type of restaurants I'm curious when the jobs are done and POS equipment is installed how much of it even connects directly to the receptacles?

Most of the equipment I see in other retail businesses gets powered from wall warts/power bricks, USB or PoE. I looked online at some restaurant POS systems and found the same. Much of it is PoE to allow simple installation, data and power with 1 cable.

Basically most of the equipment out there doesn't connect to the EGC.

Brilliant! Isolated ground receptacles for a two-prong wall-wart.