Wiring in a Fan and Light in Middle of Circuit - Problems

15 years ago

My dad-in-law and I are wiring in a a new fan/light combo in the bathroom

Here is a drawing of our wiring diagram:

The problem is, voltage measured across each terminal and ground, at the switch, measures 120V. Therefore if the ground-wire touches the metal box, it sparks and blows the fuse.

Did we mess something up?

Sort by:Oldest

Comments (4)

Ron Natalie
15 years ago
You betcha you messed something up (not the least of which was the link to the picture).

Voltage between some switch terminals and ground are expected to be 120V. However the ground and the box should be at the same voltage (zero), there should be no way on earth that the ground wire touching the metal box should spark.
petey_racer
15 years ago
I bet you have a hot wire on the ground terminal of the switch.
Related Discussions
mysterious wiring problem bathroom fan
Q
Comments (4)
The hot "white" wire is tradition for the feed from a switch loop (this is OK). The white going to the bare grounds is NOT OK. My guess is that originally this only had the switchloop in it (probably for the light alone) and someone kludged in the fan circuit as a non-switch loop. The problem is while there was a hot in the box, there was no neutral so the IDIOT connected the fan neutral to the ground. You need to fix this: 1. Either run power (hot, neutral, ground) to the fan and use what's running to that box as a switch loop (similar to what you have for the light switch) -or- PREFERABLY Run proper power (hot, neutral, ground) to the switch box for the fan. This is actually what is required by the later codes.
...See More
Outside Light Wiring Problem
Q
Comments (1)
Hopefully there's a conduit under the drive and you can just pull new wire through; however if not, boring is the way to go. Here is a link that might be useful: Boring
...See More
bathroom circuit wiring
Q
Comments (4)
Normel, sorry for the link. I guess only I have access. It's pretty simple - Switch outside the door to Bathroom. Along the inside wall, in order starting from the door--- receptacle, light over vanity, (switch for vanity light?). Exhaust fan/light unit overhead in ceiling. I was thinking of one dedicated 20A feed for the Bathroom, including the two light fixture units and the receptacle. I will have a separate 20A AFCI circuit which will feed the lights (2) and receptacles (8) for the two small bedrooms. Thanks, Ted
...See More
Wiring Help - 3-Way Circuit, 2 Lights
Q
Comments (9)
"I admittedly did not try just isolating the box ground from the bundle to see if that was the culprit." Well, check it. I am going to assume you have a metal octagonal box with nonmetallic sheathed cable running into it. First, you have too many wires in the box if it is a standard box. Second, you might have two cables under one clamp in the box. If someone tightened the clamps too tight, especially if there are too many cables in them, and then someone forced too many wires into the box, you could have enough damage to a hot wire's insulation at the clamp to cause the problem. Make sure that the metal of the light fixture over the box is isolated from the metal junction box as well, or you would be shorting out through an alternate route.
...See More
terces
Original Author
15 years ago
Well, it is confusing for us at least.

We certainly were surprised when the ground wire sparked. We've disassembled and reassembled the circuit three times now, and the same outcome happens every time.

There certainly is no hot wire on the ground terminal of the switch, unless they changed colors on me and the green screw is no longer ground.

P.S. How is the link to the picture messed up?
maryland_irisman
15 years ago
Thanks for trying to give us a drawing but it really doesn't detail how things are hooked up. From the sounds of it, you have something cross wired. Can you read a volt meter? how many volts do you have between the ground wire and the box? The reason I ask is the breaker should have tripped. If you have a lower than 108-125 volts, theres a short in one of the loads. Since it wasn't happening before, it's got to be in the new fan or, the circuit you are adding.

Related Stories

HOUSEKEEPING 10 Problems Your House May Be Trying to Show You

By Mitchell Parker

Ignore some of these signs and you may end up with major issues. We tell you which are normal and which are cause for concern

Full Story

REMODELING GUIDES The Hidden Problems in Old Houses

By Matt Clawson

Before snatching up an old home, get to know what you’re in for by understanding the potential horrors that lurk below the surface

Full Story

143

ACCESSORIES How to Hide Those Messy Wires

By Scheer & Co. Interior Design

Untangle Yourself From Ugly Electrical Cords With a Few Tricks and Accessories

Full Story

MORE ROOMS Home Tech: Getting Rid of Wires Without Sacrificing Sound

By Laura Heller

Wireless home technology still isn't perfect, but new products are giving audiophiles choices

Full Story

KITCHEN DESIGN How to Choose the Right Hood Fan for Your Kitchen

By The Sky is the Limit Design

Keep your kitchen clean and your home's air fresh by understanding all the options for ventilating via a hood fan

Full Story

153

KITCHEN APPLIANCES Love to Cook? You Need a Fan. Find the Right Kind for You

By The Sky is the Limit Design

Don't send budget dollars up in smoke when you need new kitchen ventilation. Here are 9 top types to consider

Full Story

LIGHTING 10 Chandeliers for People Who Don't Like Chandeliers

By Fred Albert

Get all the chandelier benefits without channeling Liberace, thanks to wood, paper, wire — and even a surprising old-fashioned staple

Full Story

CEILINGS Ceiling Fans: Some Spinning Sensations

By decordemon

How to Match Your Fan With Your Space and Keep Cool in Style

Full Story

KITCHEN OF THE WEEK Kitchen of the Week: Fans of Traditional Style Go For a ‘Mad Men’ Look

By Mitchell Parker

The TV show inspires a couple to turn their back on the style they knew and embrace a more fun and funkier vibe in their kitchen

Full Story

105

DECORATING GUIDES 21st-Century Looks for Shabby Chic Fans

By Becky Harris

How to update a style that's been popular since the 1990s? With new colors, crisper lines and contemporary settings

Full Story

Wiring in a Fan and Light in Middle of Circuit - Problems

Comments (4)

Ron Natalie

petey_racer

Related Discussions

terces
Original Author

maryland_irisman

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

Wiring in a Fan and Light in Middle of Circuit - Problems

Comments (4)

Ron Natalie

petey_racer

Related Discussions

tercesOriginal Author

maryland_irisman

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

terces
Original Author