Correct?
- Thread starter paulmars
- Start date
mike93lx
ALLIANCE MEMBER
Correct in what regard? Looks like a mess to me. Where is the box? What's the receptacle attached to?
It looks like the meter will function, if that's all you are after
It looks like the meter will function, if that's all you are after
The meter wires are wrapped around and soldered to the 8awg right before those go into receptacle.
The cable will be attached to wall once cover plate is installed. I know it should be sheathed, but considering its short length & protected location, I decided not too.
The cable will be attached to wall once cover plate is installed. I know it should be sheathed, but considering its short length & protected location, I decided not too.
kaymccampbell
Well-known member
How big a load are you putting on that receptacle?
Here, we use 6awg for a 50 amp circuit. Although 8ga wire is rated at 50 amps, there's some NEC rule about breaker size and circuit ampacity that jumps you up one size.
Here, we use 6awg for a 50 amp circuit. Although 8ga wire is rated at 50 amps, there's some NEC rule about breaker size and circuit ampacity that jumps you up one size.
26a kiln. Might be pulling 26a for over 3hours. Therefore 35a breaker and 8, not 10 awg. Kiln came from factory with 6-50 plug and 6awg cord. Confirmed w\factory it pulls max 26a and since it is a resistance load i measured resistance with dvm. 9.3 ohms.
If that's how you want to do it go for it. But I wouldn't seek advice or approval here after the fact.
kaymccampbell
Well-known member
Yeah, kilns do come with massive cables and plugs. Our smallest kiln, which could run off an extension cord, is cabled like it's a 200 amp welder.
The meter wires must be fine, cause the kiln manufacturers stuff the meter wires in with the mains wires. And they would never do anything sketchy.
As for exposed NM. Absolutely stick it in some conduit, or something. The **** nicks like it's made of butter.
I did not ask for advice approval. Is this electrically correct and safe? I am open to advice or suggestions.
This is my home and I dont always follow code, as long as i do it safely and not in ignorance. I like to know the codes and reasons and safety implications before i choose to break them. Im not asking anyone here to agree with what or why. Just tell me what you think from a code and safety prospective, like mentioning that wire should be sheathed. Thank you.
This is my home and I dont always follow code, as long as i do it safely and not in ignorance. I like to know the codes and reasons and safety implications before i choose to break them. Im not asking anyone here to agree with what or why. Just tell me what you think from a code and safety prospective, like mentioning that wire should be sheathed. Thank you.
Ill consider the conduit, tks
Dont understand about the kiln manu comment. Is yours a newer kiln with electronic control? Ours has a sitter.
kaymccampbell
Well-known member
Accidentally bang a mold or shatter a piece of bisque against that NM and you'll be signing up for conduit.
We've currently just got sitters and electronics, but in the day, we had a few full manual kilns, too. And meter wires always irritated me. I used to put eyelets on them, so they'd get pinned better, but wrapped and soldered gets you less contact with the wire clamps.
This is my gurls kiln, so I don't know much about them. She knows more, but not much. Just from using them in class where they were against the wall with no clearance.
I thought electronic kilns had no sitter. Her two have sitter and a heat setting knob. Nothing else.
My solder is outside of the receptacle clamp. Look closely at pic.
I thought electronic kilns had no sitter. Her two have sitter and a heat setting knob. Nothing else.
My solder is outside of the receptacle clamp. Look closely at pic.
kaymccampbell
Well-known member
Then that's more of a no. Kiln wiring gets warm. There are days when things don't go right and I've seen kiln connections heat up enough to melt solder. Mechanical connections only. Crimp that meter wire into eyelets, then crush the eyelet into the wire clamp on the receptacle.
Usually electronic kilns have no sitter. Older ones had both. Right now we've got 2 electronic kilns and one sitter. The electronic have proved to be more reliable on the temperature than the sitter and cones. But, you run what you've got til it dies.
laser3kw
Well-known member
Wait a minute....
that set of statements contradicted itself.
first you say that you are not asking for advice and then you ask for advice and you end by saying you are open to advice?
.BTW - what is a "gurl"? my spell check doesn't recognize it
ps - I have found that "temporary" and "I'll fix it later"usually means "forever"
RPH
Well-known member
In my experience working with heat treat equipment which includes ovens. Anything that wired into or onto the oven surface had high temperature wire that was sleeved with further protection.
With my experience. I say no. Not correct, possibly unsafe.
With my experience. I say no. Not correct, possibly unsafe.
dave*99
Well-known member
Where is that black interface box located relative to the heat of the kiln? It's won't last long at any sort of elevated temperature.
Is that the terminal box for the kiln? If so, no electronics belong in there.
Consider a disconnect attached to the wall and a properly rated whip to connect the kiln to the disconnect. Put the metering circuitry in the disconnect. An inexpensive air conditioning disconnect would work.
Is that the terminal box for the kiln? If so, no electronics belong in there.
Consider a disconnect attached to the wall and a properly rated whip to connect the kiln to the disconnect. Put the metering circuitry in the disconnect. An inexpensive air conditioning disconnect would work.
i knew Id get hit with that. Keep things in context. That was my reply to "If that's how you want to do it go for it. But I wouldn't seek advice or approval here after the fact." So, I stated "I didnt ask for advice or approval (in my OP). Is this electrically correct and safe? I am open to advice or suggestions."Wait a minute....
that set of statements contradicted itself.
first you say that you are not asking for advice and then you ask for advice and you end by saying you are open to advice?
BTW - what is a "gurl"? my spell check doesn't recognize it
ps - I have found that "temporary" and "I'll fix it later"usually means "forever"
My internet search: Gurl is Alternative form of girl.
I dont know if your PS refers to me, because i have found that temporary or later often means PERMANENT or NEVER.
the receptacle box is on cinder block wall about 3 feet above the kiln. This is on its own circuit and its breaker is located 15 feet away in the breaker box. The meter right above the receptacle monitors ambient temperature at the receptacle box.
dave*99
Well-known member
I'm still not sure what is shown in your photos. I see an electronic interface on a white panel. Is that your meter?
What is that panel? Where is that panel? Does it see temperatures greater than room temperature?
laser3kw
Well-known member
The PS is to everybody - me included. This is GJ, it never hurts to throw in a "reminder" for the masses.
rlitman
Well-known member
It's a bit no-no to solder wires under a screw terminal. The solder will cold flow, and that screw terminal will loosen up over time because of that.
The right solution would be to slip both the wires together into a crimp sleeve/ferrule, crimp it, and put that under the screw. No solder.
that is back of meter with its wiring diagram above the receptacle. White metal is electrical receptacle box cover.
It will see temperature 3 feet above the top of the kiln.
the solder didnt cold flow. I know how to properly heat both metals as i apply solder. my solder is not anywhere near the receptacle screw terminal.
Im now considering and researching crimp sleeve/ferrule.
laser3kw
Well-known member
Seriously, I thought it was the brand name of the kiln.
wyliesdiesels
Well-known member
FYI- #8 NM-b is limited to 40a. Breaker should be changed to 40a. A 6-50r can be on a circuit protected with 40a breaker… see T210.21(B)(3)
Two or more
I dont see wire size listed there.
That is for two or more receptacles. Still looks like i comply.
I dont see wire size listed there.
mike93lx
ALLIANCE MEMBER
Yes
I did a lot of research in choosing my breaker and wire sizes. I sure hope I didnt f up there.
the meter wires are wrapped around the 8awg diameter and twisted to themselves tightly to make a good physical connection. Then soldered for good measure. I really dont see an issue unless that area got hot enough to melt the solder, which it wont.
the meter wires are wrapped around the 8awg diameter and twisted to themselves tightly to make a good physical connection. Then soldered for good measure. I really dont see an issue unless that area got hot enough to melt the solder, which it wont.
mike93lx
ALLIANCE MEMBER
If you have a 35a breaker, that's fine for 8nm, no argument there.
Lingwendil
Member
- Joined
- Aug 13, 2021
- Messages
- 16
Definitely remove any soldered connections, and run the wires bare, or with crimp ferrules for the screw terminal connections. Solder is not needed here. It will cause failure over time from thermal cycling- there's a reason they don't solder the wires on stranded wire in nearly every industry- it causes more failures over time than running the wires bare and tightening them down correctly. where the solder stopped wicking up the wire between strands becomes the week point- like a hinge. I've had to repair a ton of these types of connections made by people who decided to ignore established best practices.
alfredeneuman
Well-known member
What is the voltage rating of the breaker are you using?
The voltage rating of an AC breaker is greatly reduced when using it on DC.
For instance, a 250V AC circuit breaker can be used for up to ~60V DC. A 125V AC circuit breaker is only good for ~30V DC.
The AC current switches direction (in the US, 60Hz), and because DC is constant, the arcs are longer and will burn the contacts in the breaker up.
Edit>> 600V AC circuit breakers have a 250VDC rating.
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mike93lx
ALLIANCE MEMBER
That's good info, but did you really think that this was a DC circuit?
rlitman
Well-known member
It's not a matter of heat control. If you had a proper solder joint, solder will wick between the strands of the 8 gauge wire (if you don't have enough heat to do that much, then you'll have a cold joint that's even more dangerous for other reasons). Ideally, a mechanically clamped connection should be very similar to a crimped termination, where the screw deforms the copper enough that all air within that ring is squeezed out, leaving you with a cross section of nothing but a "solid" copper "rod" compressed by the fitting. This generally behaves nicely over time (ignoring oxide jacking or if someone were dumb enough to swap out the screw for a steel one), with thermal cycling eventually ending with the connection settling to an elastic state.
But with solder in the joint, you now have an amalgam of copper strands with solder between them under the screw terminal. So, during thermal cycles, the solder will flow out of the joint before the copper can be compressed into a single mass. Which means you'll be left with a loose screw over time. So then you go back and tighten every so often, again and again, until you eventually forget about this and sooner or later it burns up.
i.e. DON'T tin connections going into screw terminals. And they make 8AWG bootlace connectors that will work just fine for you (the uninsulated type might be better):
There are multiple issues here, and I'll just go and guess that he's talking about a 250V NEMA 6-50, since NEMA describes neither 240VAC connectors nor DC specific connectors at any voltage. Note that the NEMA 6 series is 250V rated (with minimum 300V dielectric strength), but not specific to DC or AC (1,2, and 5 series are also not AC specific, while the NEMA 7 series and up are specific to AC). This Hubbell chart is the best I've seen (most NEMA charts you find online are chock full of errors, so beware):
As for breakers, I think a lot of that depends on the manufacturer. For example, the Square D QOU series breaker sitting on my desk (QOU360) is rated for 240VAC and 60VDC, but the Square D EDB series breaker on my desk (EGB34090) is rated for 600Y, yet carries no DC rating at all. Another breaker at my desk (Square D JGA36225) has a 600VAC rating and 250VDC rating, but the book shows that there's a 500VDC variant. I happen to only use these breakers on AC circuits, but you got me thinking, and I went down to my parts shelf (my desk isn't infinitely large) to look at the breakers we use for the 540VDC battery circuits, and those ABB S5N beauties are UL/CSA listed to both 600VAC and 600VDC, and IEC listed to 690VAC and 750VDC, both at 20kA interrupt rating. So, no, I don't see a pattern here, even though what you said did make perfect sense to me, because yes, DC should be a bigger arc flash risk.
sparky 1971
Well-known member
I'm not going to bother reading all of the back and forth banter, so maybe it's already been answered. #8 NM (romex) is considered TW or UF so breakers for it are sized using the 60° column which will tell you it's a 40 amp breaker max.
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alfredeneuman
Well-known member
Yes I did. I wouldn't have posted it if I didn't.
alfredeneuman
Well-known member
I should have said "some" 600V breakers. The point is no breakers listed for 250V is listed for use with that voltage.
Summary of the concerns and my thoughts. Plz let me know if i missed or got something wrong.
It looks messy. Might this cause a safety or electrical issue?
Solder Should not be under the screw terminals. It isn't.
Should not have 2 connections under screw terminals. There is only one.
Heat from the kiln. The electrical box is located 3 feet above kiln & has a constant on temperature readout.
Cable should be in conduit. I agree.
It looks messy. Might this cause a safety or electrical issue?
Solder Should not be under the screw terminals. It isn't.
Should not have 2 connections under screw terminals. There is only one.
Heat from the kiln. The electrical box is located 3 feet above kiln & has a constant on temperature readout.
Cable should be in conduit. I agree.