23amps and 14gauge wire, only used in panel?

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mikescooling

mikescooling

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Hey guys, I'm only talking about hooking one component to another, only inside the panel. ONLY IN THE PANEL, you can use smaller wire, because the runs are shorter, is what I'm reading? It's called open air wire rating.
Found a calculator
http://www.gorhamschaffler.com/wire_size_calculator.html

http://wiktel.com/standards/ampacit.htm

And again this tread is about panel wire size from component to component. I've had a few of my threads locked for name calling, so lets be better than that. Thanks for any helpful input?
 
If you have the 14 ga wire and no 12 then I can understand why you would ask. Aside from that I would highly recommend you use 10 ga.

Its not technically free air. Free air is when the wire is suspended on poles outside. The higher ampacity is from the air circulation around the wire dissipating the heat quicker. Inside a panel it is no longer free air.

Technically you could get away with 12 ga wire as the nec says that its rated for 23 amps, but I still recommend 10 ga.
 
Good to know, thank-you Facinerous. I was reading about it and thought I'd ask. I have a boat load of wire, so I could do 10 gauge. It seemed like a good topic. I'm doing my panel build now, looks like this
 
What is the trick on connecting 10 awg to the smaller terminals, that most of the components have. For example- from the switch to the contactor.
 
The wires that control relays and contactors are not carrying a 23 amp load. These are low amperage so 14 gauge would be fine. On most applications the only 10 awg you should need would be your line in and the wires feeding the elements on the load side of a contactor or SSR.

Sent from my SCH-I510 using Home Brew mobile app
 
For control wiring, I stepped down to 24volts, so you can use much smaller wire. The panel is not finished, I have no switches or light yet, but I'm getting closer by the day. And I have to have my new BK TIG welded. Then I can brew again.
 
Yes in a cabinet is considered a free air application. When they are talking about transmission wire they are talking about wire in a cable or conduit.
 
mikescooling said:
Hey guys, I'm only talking about hooking one component to another, only inside the panel. ONLY IN THE PANEL, you can use smaller wire, because the runs are shorter, is what I'm reading? It's called open air wire rating.
Found a calculator
http://www.gorhamschaffler.com/wire_size_calculator.html

http://wiktel.com/standards/ampacit.htm

And again this tread is about panel wire size from component to component. I've had a few of my threads locked for name calling, so lets be better than that. Thanks for any helpful input?
Click to expand...

Here are the maximum ampacities for chassis wiring, which is not the same as the NEC Code ratings for the romex cable in your house walls.

#14 THHN copper wire is good for up to 25 Amps
#12 THHN copper wire is good for up to 30 Amps
#10 THHN copper wire is good for up to 40 Amps

These ratings come from The Handbook of Electronic Tables and Formulas for American Wire Gauge. This data is also in NEC Table 310-16.
 
I used 18ga behind a 6a circuit breaker on the low amperage hookups, PID power, etc.

I've used #10 for the 25a circuits with 12/3 SO for the element cords. Nothing gets hot.

NFPA 70 is the often quoted electrical code, but in my opinion, NFPA 79 is the code which fits these panels better. Unfortunately I don't have a copy of it.
 
mikescooling said:
For control wiring, I stepped down to 24volts, so you can use much smaller wire. The panel is not finished, I have no switches or light yet, but I'm getting closer by the day. And I have to have my new BK TIG welded. Then I can brew again.
Click to expand...
I did this also.... only in a much less organized way :mug:
 
Where is everyone buying their different colors of 10, 12 and 14 gauge wire? I found red and black 10 gauge at Advance auto but no green. Are you just stripping the jacket off household romex?
 
You shouldn't use automotive wire in your control panel. You should ONLY be using THHN jacketed wire. I bought my wire from home depot. If you search for "southwire THHN" you will find what you need. Again you should not use automotive wire in your control panel. Also keep in mind that 12 AWG THHN stranded wire is rated for 30amps when used in cabinet.
 
kenh said:
Here are the maximum ampacities for chassis wiring, which is not the same as the NEC Code ratings for the romex cable in your house walls.

#14 THHN copper wire is good for up to 25 Amps
#12 THHN copper wire is good for up to 30 Amps
#10 THHN copper wire is good for up to 40 Amps

These ratings come from The Handbook of Electronic Tables and Formulas for American Wire Gauge. This data is also in NEC Table 310-16.
Click to expand...

there is a lot more to consider than what the wire is rated at

such as insulation
duty cycle
type of load
etc

just grabbing a table and quoting off of it is a way to start fires
when you study electricity and the installing of electrical systems you start to understand
such as that box, is not open air
it is inside of a box, which carries rules and codes dealing with just that
wire fill, device fill. even if the wire bends 90 degrees is all factored into how many and what size.
Wires are derated, first any 14 gauge wire may only be used up to 15 amps, that is off table 310.16 of the national electric code
then we can only use 80% of its rating. then we figure where it is and how it is being used and the duty cycle it is subjected to.

14 guage will be ok for the control wiring of the cabinet, but a 23 amp load will need # 10 wire minimum.
 
Tables are exactly how electricians and control panel builders figure out what size wire to use.

Table 310.16 refers to wire in a cable, raceway, conduit or direct bury situation. Not in a chassis or free air situation. NEC Table 310.15 is were you need to look for that. Electrical wiring in NOT derated for making a 90deg bend. What you are talking about is Cat 6 cable that has requirements like that. THHN insulated wire is rated for 90C ambient temps.

http://www.barr-thorp.com/wp-content/uploads/2011/04/Digest-176-NEC-Tables.pdf
 
Yes 310.16 ( Now its 310.15(b)(16)) shows THHN being a 90 degree conductor and list the amperage as such but the wire can only be rated as high as the terminations are rated. 99.9999% of the time this is 75 degree. This means the wire has to be rated to the 75 degree column. Also wire in an enclosure id NOT considered in free air. Box fill, bend radius, and such must be considered for rating conductors.

Sent from a red Solo cup with string connected......
 
martianpc said:
Where is everyone buying their different colors of 10, 12 and 14 gauge wire? I found red and black 10 gauge at Advance auto but no green. Are you just stripping the jacket off household romex?
Click to expand...

The insulation on the wire sold at Advance Auto is only rated at 60 Volts, household wire is rated at 600 Volts. LOWES only sells the correct stranded cable in 600 foot spools and ROMEX is solid wire.

I'm lucky, my brother in-law is an electrician and he brought over enough stranded THHN cable to wire my entire setup. Maybe someone needs to do a group buy from LOWES or Home Depot and share with the others?
 
MagooBrew said:
Yes 310.16 ( Now its 310.15(b)(16)) shows THHN being a 90 degree conductor and list the amperage as such but the wire can only be rated as high as the terminations are rated. 99.9999% of the time this is 75 degree. This means the wire has to be rated to the 75 degree column. Also wire in an enclosure id NOT considered in free air. Box fill, bend radius, and such must be considered for rating conductors.

Sent from a red Solo cup with string connected......
Click to expand...

It's the insulation not the wire that has the temperature rating.
 
MagooBrew said:
Yes 310.16 ( Now its 310.15(b)(16)) shows THHN being a 90 degree conductor and list the amperage as such but the wire can only be rated as high as the terminations are rated. 99.9999% of the time this is 75 degree. This means the wire has to be rated to the 75 degree column. Also wire in an enclosure id NOT considered in free air. Box fill, bend radius, and such must be considered for rating conductors.

Sent from a red Solo cup with string connected......
Click to expand...

I was refering to the statement that putting a 90 deg bend in the wire derates the wire. Not that the wire is derated at 90c

Also box fill ratings are base on transmission wiring. IE you can only have X number of conductors in a 4x4 box.
 
A 90 degree bend increases wire fill
and wire fill is a factor in derating

as said in another thread which you seem not to want to take the moderators advice. stop argueing till he has time to handle such

but I see your reputation is what you are arguing now, I am not going go into someone grasping for strws
 
You continue to confuse chassis wiring and transmission wiring. Also you are searching me out to post your opinion. If anyone is trying to save face it is you. So talk to someone else.

Boxes and Conductor Fill Capacity

The code requires that all outlet and junction boxes have sufficient space for the use they are put to, and there are charts and formulas for determining those capacities. However, my advice is that whenever possible you just use the large volume boxes. The bigger boxes will cost a few cents more, but they will save time and effort when you are trying to fit your connections neatly inside them. But just in case you must pinch every penny: Based on the following chart each #12 conductor that enters a box needs 2.25 cubic inches with the exception of the grounding conductor which requires one 2.25 cubic inch for all of the grounds. Also, each strap containing one or more devices is counted as the equivalent of two conductors.
VOLUME REQUIRED PER CONDUCTOR
#14 - 2 cubic inches
#12 -2.25 cubic inches
#10 -2.5 cubic inches
#8 - 3 cubic inches
#6 - 5 cubic inches
Just add up all of the values for each conductor, and compare it to the fill capacity stamped on the junction box.
Click to expand...
 
kenh said:
It's the insulation not the wire that has the temperature rating.
Click to expand...

Yes and this is calculated by the termination rating when tested for UL listing. X size wire will carry Y amps and not exceed Z temperature when terminated properly.

Sent from a red Solo cup with string connected......
 
Panels are usually wired with MTW (machine tool wire). It has more strands and does not have the nylon jacket, which makes it more flexible. THHN is good too, just not as easy to work with.
 
Now reading the chart for MTW the ratings are different then the ratings for THHN. So you would have to make sure you are reading the correct chart and looking for the correct insulation type for the chart you are using.
 
I can't really agree that one should only use THHN/THWN wire. Those wire types are most certainly the most accessible though. All I would recommend that that one chooses the right wire size and type for their application.

I recently wired a small cabinet for use with temperature control. The cheapest wire I could get was XHHW as it was was free to me. The jacket is super tuff though, my only gripe with the wire. It does meet all my requirements though, so that counts.

There are many factors when considering the wire size if you are going to choose to cut it close. If someone asks me if 14ga wire can handle an ampacity that is pushing the wires limits. I will tell them the truth to the best of my ability, and recommend what I consider the safest. If you goto Home Depot and get a 20 ft cut of wire, the price comparison is almost negligible between 14, 12, and 10 ga. wire. The major price difference is when you are buying 500 ft rolls. Then the difference can hurt the old bank account.

Please also note that the OP has a small transformer and two SSRs in the enclosure from what I can tell. There will certainly be some additional heat thrown off from these devices. Although everything looks good to me from what I saw from the pictures, you have to recognize the fact that if you are going to use a wire that is within 2 amps of the over current threshold for a conductor you could easily achieve a resistive wire snowball effect. Though I don't think a failure in the cabinet would burn down the house, it would most certainly smell, and cause more failures within the system.
 
crazyirishman34 said:
You continue to confuse chassis wiring and transmission wiring. Also you are searching me out to post your opinion. If anyone is trying to save face it is you. So talk to someone else.
Click to expand...

I don't know if I am meantioning the same thing as you in a different way but; From the quote, is the terminology being confused - to me a outlet and JB are a place were wire enters and is terminated either to connect/split wires or terminate to a socket outlet. An outlet/JB is not a panel which includes instrumentation and/or control hardware, so it would seem that where ever that quote came from is not correct to use it for control panels.
Also the quote doesn't seem to make sense - Going by it you could have 1 conductor enter the box but with enough wire inside the box to fill it jam packed and still be OK with a tiny box. I know there is probably a bit of info left out but to not include it seems to be flawed (unless you croped that out?:eek:)
 
So there are essentially 3 situations that the NEC(National Electric Code) covers. Those are transmission, chassis, and free air. Transmission wiring is any wire that is run in a raceway, conduit, cable or direct bury. Junction boxes including a junction box that you put an outlet in fall into the transmission wiring category. Junction boxes have a fill rating based on 6in of conductor in the box.

Now a free air wiring situation is one like the over head wires on poles and the aerial service that goes to some homes.

The third type of wiring is chassis wiring. That is for example the wiring in you brewery control box. The same gauge THHN stranded wire in your control box is going to have a higher amp rating the the same wire in a conduit or cable. This is because in your control box the wire has space for air to circulate and cool the wire were in a conduit it doesn't. Honestly that is a very simple explanation and there are many other factors that apply but for this moment it will have to do.
 
crazyirishman34 said:
So there are essentially 3 situations that the NEC(National Electric Code) covers. Those are transmission, chassis, and free air. Transmission wiring is any wire that is run in a raceway, conduit, cable or direct bury. Junction boxes including a junction box that you put an outlet in fall into the transmission wiring category. Junction boxes have a fill rating based on 6in of conductor in the box...
Click to expand...

So I understood you right then :)
And the OP of the comment that you qoute did miss out a big condition with the 6" Max wire in the JB
 
Facinerous said:
I can't really agree that one should only use THHN/THWN wire. Those wire types are most certainly the most accessible though. All I would recommend that that one chooses the right wire size and type for their application.

I recently wired a small cabinet for use with temperature control. The cheapest wire I could get was XHHW as it was was free to me. The jacket is super tuff though, my only gripe with the wire. It does meet all my requirements though, so that counts.

There are many factors when considering the wire size if you are going to choose to cut it close. If someone asks me if 14ga wire can handle an ampacity that is pushing the wires limits. I will tell them the truth to the best of my ability, and recommend what I consider the safest. If you goto Home Depot and get a 20 ft cut of wire, the price comparison is almost negligible between 14, 12, and 10 ga. wire. The major price difference is when you are buying 500 ft rolls. Then the difference can hurt the old bank account.

Please also note that the OP has a small transformer and two SSRs in the enclosure from what I can tell. There will certainly be some additional heat thrown off from these devices. Although everything looks good to me from what I saw from the pictures, you have to recognize the fact that if you are going to use a wire that is within 2 amps of the over current threshold for a conductor you could easily achieve a resistive wire snowball effect. Though I don't think a failure in the cabinet would burn down the house, it would most certainly smell, and cause more failures within the system.
Click to expand...

I ran 10 gauge for the elements, the lights and switches will be low voltage 24volts (for the most part). I'm still thinking about putting in a fan?
 
Well I don't know what wattage your devices would be putting out, a fan may not be necessary. It looks like you have the SSRs attached directly to the panel shell. So your panel will be doing its best to suck the heat from them and dissipate. I don't think you need to worry to much about it. If you do encounter heat problems I would recommend cutting in a louver to allow air to flow. Once again I don't think its necessary, but you'll figure it out as you put things to test.

Good luck dude.
 
I can tell you that I used 12 gauge to wire everything inside my panel. And yes 12 gauge should be able to handle 22 amps. During my test runs I checked amp draws on all of the wiring, all was good. After 30 minutes I could feel the wires getting really warm. I replaced all of my contactor wiring to 10 gauge and now it stays cool. Just my 2 cents from 3 weeks ago.
 
One thing that can cause the wire to heat up is poor connections. It is not necessarily undersized wire. I used 12awg stranded THHN in my 25a circuits and it stays cool to the touch even at full load from a 5500w element for a hour. But i used a ratchet crimper and din mounted distribution blocks.
 
crazyirishman34 said:
Yes I agree that MTW is an good choice also. But it is hard to find in short lengths and the ratings are different then THHN/THWN.
Click to expand...

I believe the ratings are the same except that THHN is for wet locations - Hopefully one's control cabinet isn't wet inside..

I used THHN because MTW wasn't available at the hardware store I shop at - had it been available, I'd've used that instead as it is much easier to dress the panel with MTW.
 
atoughram said:
I believe the ratings are the same except that THHN is for wet locations - Hopefully one's control cabinet isn't wet inside..

I used THHN because MTW wasn't available at the hardware store I shop at - had it been available, I'd've used that instead as it is much easier to dress the panel with MTW.
Click to expand...


THHN is for high heat
THWN is for wet locations

From looking at the ampacity charts 12awg THHN/THWN is rated at 30a and MTW is rated for 20a. Both are stranded.

I have never used MTW insulated wire so I can't comment on it's properties. I was just looking at the charts.
 

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