Adding a grounded outlet to ungrounded circuit.

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Old 01-04-08, 10:46 AM
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Adding a grounded outlet to ungrounded circuit.

I have a 20A fused circuit which powers the upstairs lighting in the dining room and living room. There are 11 60-watt lights on this circuit and it is wired from the fusebox with ungrounded NM type cable. I would like to add a grounded receptacle to this circuit for a laptop computer.

My plan is to run new NM w/ground cable from the fusebox to the location of the receptacle, then connect the existing lighting wiring at the receptacle location.

Is it legal to do this, or must a replace the wiring for all the lighting as well?
 
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Old 01-04-08, 11:06 AM
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Just ad the new receptacle and leave the rest alone. As soon as you start alotering the old circuit it needs be brought up to the current code.
 
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Old 01-04-08, 11:47 AM
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I don't have another fuse location to add the receptacle. It must be on this circuit.
 
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Old 01-04-08, 12:04 PM
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Ungrounded circuits are not permitted to be extended.

My plan is to run new NM w/ground cable from the fusebox to the location of the receptacle, then connect the existing lighting wiring at the receptacle location.

Why would you extend the circuit from both ends?
 
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Old 01-04-08, 12:04 PM
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You wrote, "fuse". Are you saying this is a fuse box not a breaker box? If a fuse box you may need to add a sub-panel or replace the whole fuse box with a breaker box. If a breaker box you may be able to use half size breakers depending on make and model of breaker box. and current number of full size breakers If not you can add a sub panel.
 
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Old 01-04-08, 12:37 PM
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Yes, this is a fuse box. I am not extending the circuit from both ends. The existing wiring travels in the crawlspace to the living room, where it goes up the wall to the lights. My receptacle will be placed in the wall where the existing cable runs. I would be replacing the old cable from the fuse box to where the receptacle will be with grounded NM, then attaching the existing wiring at the receptacle location. I'm not really extending anything... just replacing a section of existing wiring with a grounded version.
 
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Old 01-04-08, 01:19 PM
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The existing wiring is ungrounded. You can not connect to your new grounded circuit unless you upgrade it to grounded cabling. As soon as you work on an ungrounded circuit you must bring that entire circuit up to current code which means grounding it. Leave it alone or replace it all.
 
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Old 01-04-08, 07:19 PM
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If all you need is an outlet with 3 holes for a 3 prong cord, you may be in luck.
The National Electrical Code does not allow you to add a new grounded receptacle to an ungrounded circuit, but it does allow you to replace an ungrounded outlet with a GFCI type outlet, which has the 3 holes.

NEC 406.3(D)(3)(b)
(b) A non–grounding-type receptacle(s) shall be permitted to be replaced with a ground-fault circuit interrupter type of receptacle(s). These receptacles shall be marked “No Equipment Ground.” An equipment grounding conductor shall not be connected from the ground-fault circuit interrupter-type receptacle to any outlet supplied from the ground-fault circuit-interrupter receptacle.
 
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Old 01-04-08, 08:14 PM
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You can do that (add a GFI to an ungrounded circuit) only for a safety ground.

Your laptop requires a ground for EMI/RFI protection, which requires it be a real ground
 
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Old 01-04-08, 10:01 PM
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I'm sure a desktop computer needs a real ground, but is that really true for a laptop?
 
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Old 01-04-08, 11:11 PM
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Zombie,

What you are planning is code compliant.
You do not have to bring the entire circuit to current code.
You can extend from an ungrounded circuit but the extension must be grounded per the provisions of section 250.130(C).

From This Mike Holt article:
http://ecmweb.com/mag/electric_artic...les/index.html
“Once you add a receptacle outlet (branch-circuit extension), the receptacle must be of the grounding type and be grounded per 250.130(C)… A 3-wire system is safer than a 2-wire system. So if you add to an existing system, what you add must be of the 3-wire configuration — not the 2-wire configuration.”
 
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Old 01-05-08, 08:18 PM
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Originally Posted by Juhl View Post
Zombie,

What you are planning is code compliant.
You do not have to bring the entire circuit to current code.
You can extend from an ungrounded circuit but the extension must be grounded per the provisions of section 250.130(C).

From This Mike Holt article:
http://ecmweb.com/mag/electric_artic...les/index.html
“Once you add a receptacle outlet (branch-circuit extension), the receptacle must be of the grounding type and be grounded per 250.130(C)… A 3-wire system is safer than a 2-wire system. So if you add to an existing system, what you add must be of the 3-wire configuration — not the 2-wire configuration.”
Good catch Juhl, I missed that one. However, his options for this do not look much better than running a new circuit:

250.130(C)
Nongrounding Receptacle Replacement or Branch
Circuit Extensions. The equipment grounding conductor
of a grounding-type receptacle or a branch-circuit extension
shall be permitted to be connected to any of the following:
(1) Any accessible point on the grounding electrode system
as described in 250.50
(2) Any accessible point on the grounding electrode conductor
(3) The equipment grounding terminal bar within the enclosure
where the branch circuit for the receptacle or
branch circuit originates
(4) For grounded systems, the grounded service conductor
within the service equipment enclosure
(5) For ungrounded systems, the grounding terminal bar
within the service equipment enclosure
FPN: See 406.3(D) for the use of a ground-fault circuitinterrupting
type of receptacle.
On second thought, I guess it would be cheaper to run a ground out to the ground rod or to the main panel...
 
  #13  
Old 01-06-08, 09:47 AM
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You can add a GFCI without a ground as long as you use the little stickers that say "No Equipment Ground "

Fuses blow, no pun intended. I'd think seriously if the current box is out of room and you plan on doing some upgrades in the future. May be time for a nice big breaker panel
 
 

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