Range 4-Wire?
- Thread starter Mike01
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jumper
Senior Member
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- 3 Hr 2 Min from Winged Horses
250.140, 2008 nec
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
In a nutshell, for an existing circuit, the receptacle, the plug and cord, and the appliance should match the supply. For a new installation, go with 4-wire.
Sierrasparky
Senior Member
- Location
- USA
- Occupation
- Electrician ,contractor
I wish to differ slightly with Larry. If you need a new cord and since the recptacle is cheap I would change it out to 4 wire.
The frame of the oven should not be bonded to the nuetral as EMF and net currents could increase and cause problems with RF as well as some people complain of health issues.
This goes along with the fact that many motion sensors do not have nuetral connection and use ground as a conductor. The UL allows this but when you miltiply this by many devices in home/office to save energy you wind up with large ground currents. You may even have issues with AFCI breakers. Fortunatly most motion sensor companies are providing more choices of devices with nuetrals.
The frame of the oven should not be bonded to the nuetral as EMF and net currents could increase and cause problems with RF as well as some people complain of health issues.
This goes along with the fact that many motion sensors do not have nuetral connection and use ground as a conductor. The UL allows this but when you miltiply this by many devices in home/office to save energy you wind up with large ground currents. You may even have issues with AFCI breakers. Fortunatly most motion sensor companies are providing more choices of devices with nuetrals.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Cost of a new cord and receptacle is not the issue. The cost of repulling a new cable is the real issue. Most old cables are 3 wire not 4 wire so changing the cord and receptacle do nothing at all without the wire change.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Not with a 3-wire circuit!
Quote:
Originally Posted by Sierrasparky
I wish to differ slightly with Larry. If you need a new cord and since the recptacle is cheap I would change it out to 4 wire.
When a 3 -wire was allowed the common method here was to use 6 AWG AL SE cable for ranges & dryers so no 4-wire option avail. Tract housing here is CA is "All in One" panels so it worked since the circuit(s) originated from the service equipment.
Originally Posted by Sierrasparky
I wish to differ slightly with Larry. If you need a new cord and since the recptacle is cheap I would change it out to 4 wire.
When a 3 -wire was allowed the common method here was to use 6 AWG AL SE cable for ranges & dryers so no 4-wire option avail. Tract housing here is CA is "All in One" panels so it worked since the circuit(s) originated from the service equipment.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
If the supplying circuit is 3-wire, a 4-wire receptacle should not be installed.
That would be telling someone the circuit is 4-wire, which it wouldn't be.
Sierrasparky
Senior Member
- Location
- USA
- Occupation
- Electrician ,contractor
I never meant to place a 4 wire recept on a 3 wire cable nor did I mean to pull a new wire.
In most all the installations I have seen a 3 wire plus ground was used and the nuetral tied to the frame using a 3 pole range outlet. Most of these instances where fed from a sub panel. So replacing the outlet was no big deal. In rare instances There was 10-2 w ground pulled to dryers which was never allowed at the time of construction.
In most all the installations I have seen a 3 wire plus ground was used and the nuetral tied to the frame using a 3 pole range outlet. Most of these instances where fed from a sub panel. So replacing the outlet was no big deal. In rare instances There was 10-2 w ground pulled to dryers which was never allowed at the time of construction.
jxofaltrds
Inspector Mike®
- Location
- Mike P. Columbus Ohio
- Occupation
- ESI, PI, RBO
What level of mg (milligauss) are you reading?
Next time I remember I'll check a range with my Gaussmeter.
Sierrasparky
Senior Member
- Location
- USA
- Occupation
- Electrician ,contractor
I worked with a company called Field Management. They would get referrals from the POCO. Every instance that there were unnecessary levels of EMF it was allways due to Nuetral to ground connections. That is every call I was on. If I remenber we saw anywhere between 10 an 20 MG
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
I believe many say anything over 2 mg is not good but that would depend on where the readings were made from.
Neutral to ground connection past the load will cause unnecessary EMF's. Two neutrals from different circuits that are tied together after the load will also cause emf's as well as neutrals not run together with the ungrounded conductor.
jxofaltrds
Inspector Mike®
- Location
- Mike P. Columbus Ohio
- Occupation
- ESI, PI, RBO
That sounds high.
Dennis I am not in disagreement but 3mg is what I have heard. No scientific proof.
I have two book on EMF given to me by the publisher (now retired) for Battelle.
I doubt if anyone could understand what is in these books.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Whew!
Many of those I've seen had 10-3 without ground, too. Either way is correct.
That's still wrong. A sub-panel is like a mobile-home service, which has required major appliances on 4-wire circuits for many years.
Sierrasparky
Senior Member
- Location
- USA
- Occupation
- Electrician ,contractor
Those installs with the 3 wire no ground originated from sub panels without seperate ground and nuetral. In other words bonded nuetral sub panel .
The real doosy was a 10-2 that was on a three prong outlet and fed from a sub panel.
I told the customer no can do need to add a new wire 10-3 w ground or she could get a dryer that is 240 only.
The real doosy was a 10-2 that was on a three prong outlet and fed from a sub panel.
I told the customer no can do need to add a new wire 10-3 w ground or she could get a dryer that is 240 only.
jxofaltrds
Inspector Mike®
- Location
- Mike P. Columbus Ohio
- Occupation
- ESI, PI, RBO
Whew!
Many of those I've seen had 10-3 without ground, too. Either way is correct.
That's still wrong. A sub-panel is like a mobile-home service, which has required major appliances on 4-wire circuits for many years.
Help me understand.
Old code that allowed a 3 prong for the dryer or range.
Why could it not be feed from a subpanel?
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
If you connect an old three wire to a sub panel where would you land the neutral/ground....? Remember these cables had to be a seu or ser cable-- obviously 3 wire it was an seu cable. Where would you land the bare conductor?
jxofaltrds
Inspector Mike®
- Location
- Mike P. Columbus Ohio
- Occupation
- ESI, PI, RBO
On the neutral bar.
broadgage
Senior Member
- Location
- London, England
Two reasons AFAIK, firstly an open neutral on a 3 wire range circuit could result in 120 volts on the frame of the appliance which would clearly be dangerous. Feeding from a subpanel would increase the risk of an open neutral on account of the greater number of connections, each with a small but real risk of failure.
Secondly any voltage drop in the neutral would appear on the frame of the appliance and perhaps be noticed as some people are sensitive to low voltages. Voltage drop is likely greater at a sub panel than close to the service equipment.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
My belief is because the main panel is where the neutral is bonded, and we're relatively sure that point is zero volts to earth, whereas in a sub-panel, where the neutral and EGC are (supposed to be) separate, we can not presume that.
In other words, for the same reason neutrals and EGC's are supposed to be separated beyond the main disco enclosure.
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