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THWN wire; Gray pvc Conduit; and GFCI receptacles

9K views 29 replies 10 participants last post by  Dave632 
#1 ·
Hello- I am in need of some help. I am in the midst of installing two exterior lamp posts and two receptacles. My intent is to run the two lamp fixtures on one 15-amp circuit using 14-2 (plus ground) wire; and a separate 20-amp circuit for the two receptacles using 12-2 (plus ground) wire. The run is less than 100'. I'm not concerned about the voltage drop.

I've trenched down 18" and placed the 3/4" gray PVC piping in position. I Went to my local home improvement center to buy the wire. I understand that there are some wires that have what seems to be a dual rating: THHN (high heat resistant) and THWN (heat & water resistant).

The particular brand that is in stock is the SIMpull romex type NM-B for indoor applications; manufactured by the South Wire Co.; it is obviously not rated for wet locations- I verified this at their web site- the wire is a THHN rated wire; contrary to what the clerk working in the electrical department of the home improvement center said. He recommended that I could still use the wires by stripping the outer sheathing and running the wires through the conduit.

My first question is, should I trek over to an electrical supply house and buy the single solid strand of THWN of each gauge wire (by color, e.g black, white, & green) to be code compliant?

Does the ground wire have to be coated or can it lay bare in the conduit? (Remember, if I follow the store clerk's instructions- predicated that his wire was THWN rated, I would be sleeving a bare copper wire through the conduit- where condensation will build up at the very least.)

RE: the receptacles, should they both be GFCIs (exterior rated, of course)?

Thanks in advance! ~Buzzy
 
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#2 ·
Welcome to DIY...

First off....you don't want to be pulling any type of romex through conduit.....while it can be done, it's not easy and sort of defeats the purpose of the conduit....especially 100'.

Get some THWN stranded wire (all 3 colors) and pull that through the conduit. The rolls will likely come in 500' lengths, so it if was me...I would just use the same wire for the lamps instead of using 14awg. As fas as I know, it's ok to use 12awg on a 15A breaker. You just can't go the other way around.

Is the conduit going straight to your load center? If so...makes life easier....just terminate the wire in the load center.

However, on the load side...using stranded wire takes an extra step or so. Lights are easy...wire nut....but on the outlets, unless it is the type with a back plate on the screw, then you either have to use a pigtail with solid wire to the outlet or crimp connectors on the wire and then the connector screws to the outlet.

Personally....I prefer the crimp connectors if it's just one connection...but if your branching off to more than one outlet....then pigtail it.
 
#4 ·
....but on the outlets, unless it is the type with a back plate on the screw, then you either have to use a pigtail with solid wire to the outlet or crimp connectors on the wire and then the connector screws to the outlet.
Not correct, UL lists receptacles for both solid and stranded conductors.

Twist strands CCW and they terminate just fine on screw terminals.
 
#3 ·
You cannot use romex (NM), or the conductors inside the outer sheathing underground or outside. You will need to purchase individual THWN. The ground can be bare, but I would purchase a green #12 for the run.
 
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#6 ·
Thank you for your replies. I was told the following, " Ground Fault Circuit Interrupter (GFCI) protection for all outdoor receptacles is required
by the NEC – accomplished with an individual GFCI receptacle in each outlet box or with a GFCI breaker mounted in the service
panel that protects the entire circuit."

Any comments or suggestions? I plan on placing a receptacle on the front siding of my house and the other by the lamp post that will light my sidewalk. Is it okay to have two exterior grade GFCI receptacles on the same circuit?

A friend of mine told me that if I place the GFCI receptacle at the beginning of the circuit, it will provide protection coverage to the second receptacle down the line without having to install a second GFCI outlet at the lamp post.

Expense aside, I want to make sure that I am installing these receptacles properly- to code...safety is paramount.
 
#7 ·
You can use one GFCI receptale for both outdoor receptales and it is pretty common to do that just remember the line and load connections just don't get them cross connected otherwise they will not work useally not kick on or stay off.

Are you putting the receptales on the lamp post ? if so which style you are going to use ? that will make the differnce on them. Also with the WP ( weather proof box ) if you going to use the GFCI's use the deep well verison due you will have more room to work around with them. ( they worth extra cost for deepwell verison )

Merci,
Marc
 
#9 ·
Hello- I am in need of some help. I am in the midst of installing two exterior lamp posts and two receptacles. My intent is to run the two lamp fixtures on one 15-amp circuit using 14-2 (plus ground) wire; and a separate 20-amp circuit for the two receptacles using 12-2 (plus ground) wire. The run is less than 100'. I'm not concerned about the voltage drop.​



I've trenched down 18" and placed the 3/4" gray PVC piping in position. I Went to my local home improvement center to buy the wire. I understand that there are some wires that have what seems to be a dual rating: THHN (high heat resistant) and THWN (heat & water resistant).

The particular brand that is in stock is the SIMpull romex type NM-B for indoor applications; manufactured by the South Wire Co.; it is obviously not rated for wet locations- I verified this at their web site- the wire is a THHN rated wire; contrary to what the clerk working in the electrical department of the home improvement center said. He recommended that I could still use the wires by stripping the outer sheathing and running the wires through the conduit.

My first question is, should I trek over to an electrical supply house and buy the single solid strand of THWN of each gauge wire (by color, e.g black, white, & green) to be code compliant?

Does the ground wire have to be coated or can it lay bare in the conduit? (Remember, if I follow the store clerk's instructions- predicated that his wire was THWN rated, I would be sleeving a bare copper wire through the conduit- where condensation will build up at the very least.)

RE: the receptacles, should they both be GFCIs (exterior rated, of course)?

Thanks in advance! ~Buzzy
While your at it, you need to install a panel suitable for use as service equipment at each post and drive two ground rods at each as well.
 
#15 ·
Thank you sir for replying. Since I did buy individual lengths already, I will need to wrap one of the leads (extra length of white) in green tape to color code it as my ground since the supply house ran out of insulated ground wire. Does the green tape have to cover the wire completely by overlaying the tape to itself or can i just spiral it on leaving gaps where the white insulation will be exposed?
 
#17 ·
Unless code has changed you can't just mark the black or white wire to use it as a ground:

Unless it larger than #6 it must be "identified by a continuous green color or a continuous green color with one or more yellow stripes on the insulation or covering, except where bare."

You can strip the insulation off but no taped ends.
 
#18 · (Edited)
Buzzy said:
Just paint me gullible- my dad taught me from a very young age to do things right the 1st time- or don't do them at all. And to ask for help...or when I'm unsure or don't know the answer to a problem, to seek out the professional. So when someone like me joins a list like this to get an "on the level" answer, I am not interested in or not impressed with someone who throws out a broad answer because they have more knowledge than I. I ask out of genuine respect that I have for the tradesman or person I am seeking their assistance from, that they'll step up to the plate and educate me with their knowledge- and for my safety!
In no way am I trying to be funny. The NEC requires that any structure supplied by more than one circuit have a panel that is suitable for use as service equipment and two ground rods at each. This is a code requirement. The silence of our other experts on this thread is deafening.
 
#19 · (Edited)
I understand your point of view however I belive the OP is useing single MWBC or a single circuit avce one unswitched et one is switched so if both are from the same circuit that pretty much throw out of the window but single MWBC useally muted on this one most case but more than just a MWBC then oui I agree with that part.

Just my option on that part.

Merci,
Marc

Note I know OP mention one 15 and one 20 amp circuit however if he stick to single 20 amp circuit and use the switch loop and run from the same circuit then you should be fine on that part. Because I do not know if the OP is useing the same switch at the house side which it is on the lighting circuit.
 
#20 ·
frenchelectrican said:
I understand your point of view however I belive the OP is useing single MWBC or a single circuit avce one unswitched et one is switched so if both are from the same circuit that pretty much throw out of the window but single MWBC useally muted on this one most case but more than just a MWBC then oui I agree with that part.

Just my option on that part.

Merci,
Marc

Note I know OP mention one 15 and one 20 amp circuit however if he stick to single 20 amp circuit and use the switch loop and run from the same circuit then you should be fine on that part. Because I do not know if the OP is useing the same switch at the house side which it is on the lighting circuit.
In the original post he states one 15a circuit and one 20a circuit. Sounds like two circuits to me.
 
#22 ·
My mistake was not contacting my local inspector and a local licensed electrician for assistance

For my project that I am working on, it is okay to run the two circuits (15 amp & 20 amp) into one 3/4" gray pvc (schedule 40) conduit underground.

I do not have to "install a panel suitable for use as service equipment at each post" or drive any ground rods into the soil at each location, either.

And it is permissible to use any color insulated wire as a ground as long as it is wrapped in green coded tape. I don't have to wrap the entire length of the wire, just the portions that are exposed outside the sleeve of the conduit at the ends where the wire nut connections are made.

And yes, the ground wire must be insulated, bare copper wire cannot be sleeved into the pvc conduit.

A licensed electrician volunteered to come and inspect my work as soon as I'm done.

Thanks to everyone for their help and input. God Bless.:)
 
#23 ·
My mistake was not contacting my local inspector and a local licensed electrician for assistance
Correct

For my project that I am working on, it is okay to run the two circuits (15 amp & 20 amp) into one 3/4" gray pvc (schedule 40) conduit underground.
Correct

I do not have to "install a panel suitable for use as service equipment at each post" or drive any ground rods into the soil at each location, either.
Debatable. Do you have 2 individual circuits going to a single structure?

If yes a SUSE rated disconnecting means and a Grounding Electrode System, such as rods, are required at that structure.


And it is permissible to use any color insulated wire as a ground as long as it is wrapped in green coded tape. I don't have to wrap the entire length of the wire, just the portions that are exposed outside the sleeve of the conduit at the ends where the wire nut connections are made.
Incorrect. Insulated grounding wires smaller than #4 must have a continuous green or green w/yellow stripe insulation.

And yes, the ground wire must be insulated, bare copper wire cannot be sleeved into the pvc conduit.
Incorrect, except for a few exceptions.

A licensed electrician volunteered to come and inspect my work as soon as I'm done.

Thanks to everyone for their help and input. God Bless.:)
Good luck.
 
#24 ·
Code05 said:
Correct

Correct

Debatable. Do you have 2 individual circuits going to a single structure?

If yes a SUSE rated disconnecting means and a Grounding Electrode System, such as rods, are required at that structure.

Incorrect. Insulated grounding wires smaller than #4 must have a continuous green or green w/yellow stripe insulation.

Incorrect, except for a few exceptions.

Good luck.[/

Why is it that when they don't like the responses, they give us attitude? Code is code. If his inspector accepts less, that's on him.
 
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#26 ·
Why is it that when they don't like the responses, they give us attitude? Code is code. If his inspector accepts less, that's on him.
Why are you quoting me? I agreed with you, except that a SUSE rated panel is not required, only a SUSE rated disconnecting means is.

225.36 Suitable for Service Equipment. The disconnecting
means specified in 225.31 shall be suitable for use as
service equipment.
 
#25 ·
Why is it that when they don't like the responses, they give us attitude? Code is code. If his inspector accepts less, that's on him.[/quote]


That's very presumptuous on your part...granted, you know your NEC codes but that does not mean you know my motives or rationale for my comment, "my mistake was not contacting my local inspector and local licensed electrician for assistance". If you perceived my comment in a negative manner, that's on you.

Code5 was gracious in getting his point across without being brash or accusatory.

Pick any profession or trade- now take any number of people within that trade or profession and place them in a room. Ask the exact same query to each of those people and you'll get as many different answers as there are people. No two answers will be exactly alike. (remember playing the game telephone when you were a kid?!)

So, due to the fact that there were several different answers to my query- I recognized that the best way to resolve my dilemma was to go with what is an acceptable practice in my area/jurisdiction; plain and simple.

Having said that, as each new (building) code year evolves, do you strip down your entire electrical, plumbing, gas, framing (and so forth) to your residence to accommodate all the latest code revisions?

If the NEC (or other building codes) are cast in stone, then ALL homes built prior to 2011 are in violation to the latest codes; and are not optimized for safety/protection; and would have to be retrofitted to the current specs.

There are emergency war housing units (brick & cast stone) in town built circa 1917- (pre WWI), as well as ballooned frame homes- that are listed in the National Register of Historic Places; and that are still outfitted with 60 amp service; with 2 bakelite fuse holders (pull-out fuse blocks- marked "main & range") for ferrule type cartridge fuses & 4 glass screw fuses...and the meters are still indoor.

Now mind you, although 60 amp service is legal here in the municipality where I live, I am sure there are some jurisdictions outside my area where service is mandated to be upgraded to at least 100 amps.

Therefore, citing the above as an example, my community standards allows me to install my residential light posts and receptacles without having to install ground rods or an exterior disconnect.

As I stated in my earlier posts, I am genuinely grateful to all of you who have replied to my post for help; the varying responses prompted & encouraged me to make contact with professionals and officials in my locality. What a blessing!

Peace ~ Buzzy :)
 
#27 ·
Code05 said:
Why are you quoting me? I agreed with you, except that a SUSE rated panel is not required, only a SUSE rated disconnecting means is.

225.36 Suitable for Service Equipment. The disconnecting
means specified in 225.31 shall be suitable for use as
service equipment.
Sorry. Didn't need to quote your post. Meant it as agreeing with you. Thanks.
 
#29 ·
This is kinda of off topic related to the oringal topic however I can answer your question here #6 green is generally is not a best idea to remarked at all there is a safety issue going on is that green conductor or green conductor with yellow stripe which that is a grounding conductor so it can not be remarked to other colours at all.

#4 or larger can be done however be aware that the inspectors may nix that one pretty fast espcally with green conductors which they are remarked.

Merci,
Marc
 
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