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Question 1. I am building myself a lamp and I am using a plastic 1 gang outlet box. There are no ground wires. How can I properly ground the lamp?

Question 2: Can I attach a metal bar and place it on the wood, then attach the ground wire?

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    Is this a lamp unit that is intended to be plugged into some receptacle or is it a permanently installed fixture that is wired directly into the building wiring? – Michael Karas Sep 23 at 1:05
  • It will be plugged into a wall receptable. – Unapologetic Poetry Sep 23 at 1:21
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You get a usb charger, and wire up the lamp in 5V, going to LEDs. (There are 5V LED bulbs, or you could hardwire them in, depending on the type of lamp you're building.) There is no ground wire, but it's low voltage, so there's no safety issue.

EDIT: 12V is also good; you can use whichever is most convenient.

  • I am attaching a usb to the lamp. – Unapologetic Poetry Sep 23 at 1:20
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    @UnapologeticPoetry What this answer is saying, is do not use mains power at all in the lamp - have the lamp itself run off a wall-wart. That is actually very smart, since it renders safety and code issues entirely moot. I would use 12V, since wall-warts and LED light components are readily available for 12V. As far as making 5V for USB, every gas station sells gadgets that make USB power from 12V. – Harper - Reinstate Monica Sep 23 at 4:16
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At least in the US, it is normal for lamps to not have ground wires. As long as there are no exposed metal parts, there's really no reason to ground it.

If there are exposed metal parts, you need to insulate them from either the electrical wiring or the user somehow.

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    No, that's very bad. Never attach the chassis of equipment to neutral! Right off the bat if a receptacle is miswired the equipment chassis becomes lethal. A simple wire failure will also lethalize neutral. Code requires more "defense in depth" than that, so neutral must be insulated as a hot. You're not understanding what you see there in the breaker box, so you're reaching a very wrong conclusion. That is not a convention. Neutral is not ground. Never confuse them and never tie them together (except exactly one place, the equipotential bond in the MAIN panel). – Harper - Reinstate Monica Sep 23 at 4:14
  • I agree that it's bad practice (especially when most people replacing plugs don't know how to wire them properly), but bonding neutral to the case was a common practice for many appliances until a few decades ago (iirc it was removed from the NEC, except for some special exceptions, in the '90s). That was when I was a child and it's an outdated practice, so I may very well be missing some information. I do know that neutral might very well have some voltage on it before it is bonded to ground in the breaker box. – Nate Sep 23 at 4:48
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    You may be thinking of that on dryers and ranges, which was a weird exception that lingered into the 80s. What happened was they figured out it was killing people. If the neutral wire breaks anywhere in the system (including the common "lost neutral" out at the pole), neutral gets pulled up to a hot voltage. Anything that isn't treating neutral like a hot, is now energized. That's why it's been progressively banned, with dryers and subpanels being the last things to be banned. If the person wants to attach chassis to something, let them use a 3-prong cord. – Harper - Reinstate Monica Sep 23 at 4:58
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    Then I'll withdraw that portion of my answer - thanks for clarifying – Nate Sep 23 at 5:00

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