what's going on my friends i am dustin stelzer with electricianu and we had a question from our
youtube comments uh that i figured i would read this time and address so the question of the day
is hey dustin i'm confused about wire types like t-h-h-n t-h-w-n-e-t-c could you please make a
video about that and explain which type is for which environment thank you sean y from youtube
let's open up the code book we're in 2020 so i'm going to go to 2020. there is a part in 310
which is conductors for general wiring so there's a few different tables that look like 310
depending on if you're looking at fixture wires if you're looking for like you know things like lamp
cord and things like that or if you're looking for just general conductors so 310 covers conductors
now what you'll notice is table three 10.4a is conductor applications and installations rated
600 volts so this means these are conductors that are all rated at 600 volts and below so if you're
in like a thousand volt environment you can't use these because they're not rated for that so the
insulation around that conductor is going to break down prematurely probably melt depending on what
kind it is so you always have to make sure that you're under 600 volts for 600 volt rated stuff
so what's really interesting is there's tons of different types of conductors in here and again
it's not the conductor the conductor's just the metal part in the middle so all stranded number
12 is going to be the same as you know it's all copper you might have like some aluminum
conductors that you run out every once in a while but the aluminum is the aluminum it doesn't matter
all the aluminum is going to be the same all the copper is going to be the same solid or stranded
so the conductors are not what we're talking about here when we're sizing and ampacity we're
in 310.15 we're not talking about the actual metal inside the conductor the thing that hooks up the
wire we're talking about the insulation around it because that's the part that has all these
different ratings that's what we're sizing our amperage for when we size conductors for things
it's all to protect that insulation to see what the insulation can handle so if we talk about
doing things in wet environments or we talk about things in dry or damp environments or things that
you know like might damage something it's always talking about the insulation being damaged so keep
that in mind so in 310 we talk about all these different types of conductors we're talking about
insulation types so this entire table the left hand column is the trade name so we have things
like the very first one fluorinated ethylene propylene i don't know what that is that's
just a crazy bunch of words who made those words up steve steve made them up who is a steve guy
all right then we've got things like mineral insulation moisture heat and
oil resistant thermoplastic so there we have a term thermoplastic a lot of these you're going
to notice have that but some of them that if you notice two columns over it says maximum operating
temperature so each one of these insulation types is rated at a certain amount if we look back up
at the fluorinated ethylene propylene it says 90 degrees celsius or 194 degrees fahrenheit
uh and then down below that says 200 degrees celsius or 392 degrees fahrenheit that means that
it is dual rated it has two different ratings and usually if you look to the right one more column
under the application provisions it'll say dry and damp locations and if you look to the left
of that that's where it's rated at 90 degrees celsius or if you're in dry locations in special
applications and there's a little number three that's uh it looks like an exponent so if you
flip to the end of the table we read note 3 says higher temperature rated construction shall be
permitted where design conditions require maximum conductor operating temperatures above 90 degrees
celsius so there are special conditions that make the 200 degrees celsius to the left of that
dry locations special applications uh what you're going to be using if we look down at rhh which is
in the second column it says thermoset so rhh is a conductor that is a thermoset conductor it has
90 degrees celsius ratings which means that the heat rise in that conductor that the insulation
can actually handle a certain amount of heat rise up to 90 degrees celsius that is in dry
and damp locations so you kind of get it right all of these tables are going to be the same
now over one more column it says the insulation so it actually talks about the insulation around
that conductor so paper says paper if you have a perfluoro alcoxy it's just telling you what the
actual insulation is and sometimes the insulation is going to be different than the trade name
so you might have a trade name where we call something one thing but the rating of the
insulation is actually named a certain thing so that's just a different column then we have the
thicknesses of the insulation which just takes up three different columns and it's going to either
talk about the thickness in awg or kc mill so if we talk about number 12 conductors right it's
actually 12 awg there is no number 12 that's just something we say in the field but 12 awg is a an
actual size casey mill if you ever run like 250 uh sometimes you'll hear like 250 mcm or 300 mcm
used to call it mcm thousands of circular mils which is what the m stands for thousands um now
we say kc mill thousands of circular mils um it's just a different way of putting it
so we uh if you're looking at things for those wire sizes you're going to be looking in that
column if you're looking in millimeters you're not you know in the us for or you just use millimeters
and you're in the us i don't know you would just use the millimeter column or you can use
mills so that's just talking about the different thicknesses of the insulation
for the different conductor types and then lastly on the right column we have outer coverings so
the outer covering not every single one of these insulation types is going to have an
outer covering but you'll notice sometimes when you run like th hhn there's this extra kind of
clear coat this like clear insulation or jacketing that's around the insulation and that's just to
protect it it says extra outer covering so when you're pulling those conductors and they start
getting scuffed you're scuffing the outer layer you're not actually damaging the insulation so
it'll tell you whether or not there is an outer covering one thing to take note of is there is
a bunch of things that are called thermoplastic and there's a bunch of things called thermoset so
when we start getting into your example where you asked about th hhn if you notice there's
a whole bunch of thermoplastic conductors right next to each other so it starts out with th hhhn
and i'm on the second page of this so t-h-h-n it says heat resistant thermo-plastic if you
go down t-h-h-w well that's still a th it's still a similar thing and by the way the hh
usually if there's two h's it denotes that it's a 90 degree conductor not always
uh but most of the time the two h's means 90 degrees one h will mean uh 75 degrees
so uh any kind of th h you know it's usually going to be a uh 90 conductor the th n with the n at the
end means that there's a nylon coating around the outside of it thhw still the same conductor
pretty much it's still the th so it's still a heat resistant thermoplastic but they add the w
for wet environments so now this is a moisture and heat resistant thermoplastic so they go with th
hhw now you'll notice with th in we have a 90 degree celsius insulation type right so we can
handle a lot of heat rise in that conductor but th hhw has two ratings so it can be used
in dry locations or in wet locations when it's used in a wet location the insulation isn't as
good so you have to use the 75 degrees c it can't handle the same kind of heat rise that it can in
a dry environment so in a dry environment you're allowed to use the 90 degrees celsius both of them
are flame retardant heat resistant thermoplastic it's just that one of them is moisture resistant
one of them has a nylon jacket the th n and that and is the nylon so the other one does
not then if you move down we have th n thw then we have thw so th uh instead of it being rated
90 degrees there's only one h right so that's a 75 degree conductor but the w still denotes that it's
you can kind of think of it as like weatherproof or like wet uh right just thinking of moisture
that's why they use the w so it's a very similar conductor than all the other ones
it's just instead of it being 90 degree rated it's 75 degree rated but there are special applications
that you can use it as a 90 degree conductor as well and that's in the notes and then because
of that that whole 75 degree thing they came out with a new conductor which is thw-2 so thw-2 is
dry in wet locations 90 degree celsius conductor and it's still moisture and heat resistant so
it's technically a thw still it's just that it really the difference is thw has two different
ratings for two different environments whereas thw2 has 90 degrees celsius for dry and for wet
so you don't have to take it down to 75 degrees because you're in a wet environment on that one
so still in thermoplastic all of these are th right you can kind of think of all of the th
conductors as the same conductor with little weird modifications to them so then we've got th wn
so we've got the 1h which denotes that it's a 75 degree conductor we've got the w which is moisture
you're right you're going to be a wet environment and n gives you the nylon jacketing so that's a 75
degree conductor in dry and wet locations but just like they did with thw they gave a thw2
they gave a thwn and a thw n2 so now you have a 90 degree rating for the same nylon coated wet
environment conductor so it's still a moisture and heat resistant thermoplastic
dry and wet locations and there is a nylon jacketing around the outside of it
then the last one we've got a moisture resistant thermoplastic so now we don't have the
heat resistant properties so it's just tw there's no h so it's still a thermoplastic t and then it's
wet or uh you know moisture environment tw that is a 60 degree conductor so that's not a 75 degree
that's not a 90 degree conductor it can only handle 60 degrees of heat rise but it gives it
to you in dry and wet locations and there is no jacketing on it now before we get into the next
series of conductors uh just wanted to let you guys know we have classes available if any of you
are interested in joining some live instructor life courses you can go to electricianu.com we
have live classes available and we've lowered our prices recently the other thing is if you're
looking for continuing education it doesn't matter what state you're from uh we're actively getting
approvals in every single state in the u.s go check our electricianu.com make sure that we have
your state but we have video based continuing education which is pretty rad because then you
just get to watch these videos and then you get credit for it with your statement pretty dope
so the first thing we caught we covered was all the th conductors right th n thw and
all that stuff that is all thermoplastic next we're going to get into thermoset
so thermoset we've got things that are xh or xhhn or xhhwxhwn same kind of thing right it's
just that the the the insulation is not made from a thermoplastic it's made from a thermoset
so the difference between a thermoplastic and a thermoset is that a thermoplastic is designed
to soften when it's heated and to harden when it's cooled so what that means is that if
you heat that insulation up a whole bunch it's actually going to start to melt the insulation
that's a thermoplastic a thermoset actually means that it is insoluble and non-melting
so let's break in a little bit to these xhhw that is a 90 degree celsius conductor and it's for dry
and damp location notice it's actually not a wet environment it's a damp environment so you do have
to make some distinctions between a wet and a damp environment wet usually means submerged or like
like saturated with water damp just means that it's kind of exposed to some moisture so
an insulation around a conductor that's exposed to a little bit of moisture isn't going to degrade
you know it's going to it's going to withstand that versus it being completely submerged in water
the next one xhhn so they're still flame retardant it's the same exact conductor just has a nylon
jacketing on the outside which is why they add the n in there then they change it from
an n to a w so we have xhw so this is where we get that wet location right the w it's now this
is a moisture resistant thermoset it's got two different uh temperature ratings so dry and damp
locations it's a 90 degree conductor or if it's a wet location it's a 75 degree conductor that's
kind of universal you see that most of the time unless it's a dash two where it usually is a
conductor that can handle dry and wet and it's a 90 degree conductor so they're super super stout
uh xhwn so what do you think that means we got the w moisture resistant and nylon and then the x
means that it is a thermoset and h means that it's a 75 degree conductor for dry and wet locations
but you add the dash 2 at the end and that raises it up to a 90 degree conductor and it allows it to
be in dry and wet environments most of the time if you get anything with a dash 2 at the end of
it you're good for almost every environment but the things you have to consider are the
cost of the conductors a b what does the supply house actually have on them because they you go
to like a local supply house or you go to home depot or something like that they're not going
to have every single one of these conductor types or these insulation types so you have to kind of
know what the environment is that you're getting into and look in 310 and code and figure out all
right which kind of installations apply to the job that i'm at and now what is available to me
so hope that helps thank you so much love you guys i'll see you next one
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