Electric cooktop plug needed

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  #1  
Old 03-18-17, 08:04 PM
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Electric cooktop plug needed

Hello all!
Electric cooktop has wiring but no plug. Can anyone can tell me, which plug I need for this setup and where I can get it?

Cooktop label:
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Cooktop wires with no plug:
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Outlet to plug cooktop into:
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  #2  
Old 03-18-17, 08:25 PM
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Your cooktop is set up for a direct connection. You will need to remove that receptacle and connect the wiring to the wires that are currently on that receptacle.

It looks like that receptacle is on a 4" square plate over a 4" square junction box.

Turn the power off to that receptacle. Open the box and post a picture of the connection inside.

Also.... based on the requirements for your cooktop... you will most likely need to put a 2P40A breaker on that circuit.... instead of the 50A that may be on there now.
 
  #3  
Old 03-18-17, 08:26 PM
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That needs a Nema 10-50p plug such as https://www.amazon.com/Legrand-Pass-.../dp/B000BPFZHM

But like PJmax said what you have is designed to be hard wired.
 
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Old 03-18-17, 08:28 PM
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That cooktop, as most do, comes with an MC whip.
 
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Old 03-18-17, 08:41 PM
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You need a Nema 10-50p plug such as
You can't put a plug on an armored whip like that. It has to be directly wired. Not only that, but the receptacle that the OP has is NOT grounded, the third prong is a neutral. Wiring an EGC to a neutral prong (bootleg ground) can have deadly consequences. That's why NEC has required 4 prong connections for the past 20 years.
 

Last edited by taz420; 03-18-17 at 08:56 PM.
  #6  
Old 03-18-17, 08:45 PM
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We can't fully advise the member until we see what he has for wiring. It may be old aluminum cable which would require special handling.
 
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Old 03-18-17, 09:25 PM
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Thanks!
I'll have to open the box then come back and post a pic of the connection inside.
 
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Old 03-19-17, 06:41 AM
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Wiring an EGC to a neutral prong (bootleg ground) can have deadly consequences.
Looks like the cooktop is 240V only as I don't see white wire on the whip and the label doesn't say 120V/240V.
If so, using neutral as equipment ground will be perfectly safe.
 
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Old 03-19-17, 07:05 AM
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The unit is meant to be hard wired into a junction box. There is no cord cap for metal flex conduit.
 
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Old 03-19-17, 07:11 AM
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using neutral as equipment ground will be perfectly safe.
But not code compliant because #6 and smaller must be factory green or bare. You're correct about safe of course. Boils down to the AHJ really if an inspection is really needed. But he could have SE or individual conductors in metal conduit. Balls in the OPs court now. Inquiring minds need more info.
 
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Old 03-19-17, 09:26 AM
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OK...Here's what we're looking at:
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Side views
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  #12  
Old 03-19-17, 10:06 AM
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FWIW, I hook up cook tops on occasion and would not be allowed to install this top until a new cable with ground is installed. Same with a wall oven.
 
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Old 03-19-17, 10:31 AM
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If so, using neutral as equipment ground will be perfectly safe.
If it were "perfectly safe", why is it a code violation? There is always a risk of stray current being present on the grounded conductor due to load imbalances. If one happens to be touching the metal frame of the cooktop in bare feet (making breakfast at 6am?) when this current shows up, you'll feel it.

But not code compliant because #6 and smaller must be factory green or bare.
You mean repurposing the neutral as a ground by connecting it to the ground bar at the breaker box - which yes would be safe just not compliant with the letter of code re: reassigning the wire color. I interpreted what he said as just connecting the ground to the neutral as-is (bootleg), like Astuff suggested with putting the 10-50P plug on the end of the whip.
 
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Old 03-19-17, 11:46 AM
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FWIW: I found this, in paperwork, for cooktop, which shows connecting from power supply to the cooktop as follows: red to red, black to black and green to green via a screw in the middle of junction box. However, my wires from power supply are all green with one taped white.
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  #15  
Old 03-19-17, 11:53 AM
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What you have are all blue, not green (absolutely no offense intended, but have you been checked for colorblindness? confusing greens and blues is a prime symptom). The one that's marked white is neutral, it doesn't matter which hot is red or black. The issue you have is the ground - or lack thereof. You can not reidentify any conductor in a conduit, you must pull a new green one. We can't stop you from moving the white to the ground bar in the panel and taping it green at both ends, and there would be nothing "unsafe" about doing that... But just know that it is a code violation.
 
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Old 03-19-17, 01:40 PM
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Thanks, no offense taken.
How do I pull a new green one?
 
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Old 03-19-17, 01:52 PM
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It's individual conductors, so it's in conduit at least at that end. Now that doesn't guarantee that it doesn't transition to cable at some point though. Where is the cooktop in relation to the panel? Is there a 3/4"-1" conduit going into your panel? Have you taken the cover off the panel?

If it's not too long of a run with only a couple bends, then basically you'd need to get some 550 paracord, take the leads off the panel and receptacle, straighten out the leads, tape them together at one end, attach the paracord, and pull it all out through the other side. The paracord acts as a drag line, so then you attach the new green at the other end (technically since you're going this far, you should replace the white as well, since that too is a code violation - even if you're not using it now, you should think of the future). Then use the paracord to pull the wires back into place.

Since this can only be a 50A circuit max, you only need to pull a #10 green, it does not need to be #6. You will still need to replace the breaker with a 40A per the cooktop's requirements though..

To make the pull easier you could also replace it all with #8 red/black/white and #10 green, but that would preclude you from installing an induction cooktop in the future because those generally require a 50A circuit.
 
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Old 03-19-17, 02:06 PM
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If it is metal conduit all the way no ground wire needed. The conduit is ground. The "white" is not used. (Capped off on both ends.) The cooktop ground is fastened to the metal box. Using a multimeter either hot to the metal box should show ~120 volts.
 
  #19  
Old 03-19-17, 02:22 PM
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If it is metal conduit all the way no ground wire needed. The conduit is ground.
Not a fan of doing that. One loose locknut or coupling screw or a little rust in the right spot is all that's needed to open the ground. Would you vouch for its integrity? I sure wouldn't.
 
  #20  
Old 03-19-17, 03:14 PM
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Originally Posted by taz420
It's individual conductors, so it's in conduit at least at that end. Now that doesn't guarantee that it doesn't transition to cable at some point though. Where is the cooktop in relation to the panel? Is there a 3/4"-1" conduit going into your panel? Have you taken the cover off the panel?

If it's not too long of a run with only a couple bends, then basically you'd need to get some 550 paracord, take the leads off the panel and receptacle, straighten out the leads, tape them together at one end, attach the paracord, and pull it all out through the other side. The paracord acts as a drag line, so then you attach the new green at the other end (technically since you're going this far, you should replace the white as well, since that too is a code violation - even if you're not using it now, you should think of the future). Then use the paracord to pull the wires back into place.

Since this can only be a 50A circuit max, you only need to pull a #10 green, it does not need to be #6. You will still need to replace the breaker with a 40A per the cooktop's requirements though..

To make the pull easier you could also replace it all with #8 red/black/white and #10 green, but that would preclude you from installing an induction cooktop in the future because those generally require a 50A circuit.
Thanks!
The cooktop and the panel are on opposite sides of the same wall; they are both approx 6 paces in from end of wall. It may be a straight drop approx 3-4 feet down from panel to cooktop.

Here's some wiring that I have on hand, how do I tell what size it is?
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Panel with 2 cooktop breakers OFF (bottom left):
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Where wires drop towards cooktop:
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  #21  
Old 03-19-17, 03:21 PM
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Ok excellent. That means it shouldnt be a problem. If it really is a straight drop, you MIGHT be able to thread the new ground wire in without pulling the old ones out. No promises, but its worth a try over that short a distance.

The wire you have is #10, so you can use that green. The size is indicated by the "AWG 10" printed on it.
 
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Old 03-19-17, 04:07 PM
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Would you vouch for its integrity?
If I had a Megar I'd use that. If not I'd put a 60 watt incandescent light bulb between hot and ground and see how bright it was.

Your point is certainly valid and in this case it is too easy to run a ground wire to leave it to chance. Definitely add a ground wire.
 
  #23  
Old 03-19-17, 10:57 PM
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If it were "perfectly safe", why is it a code violation? There is always a risk of stray current being present on the grounded conductor due to load imbalances.
I think you did not see the part where I said the cook top OP has is 240V only appliance. If there is a load imbalance that causes current present on a EGC, that means you have short to ground. There will be no current present in neutral wire as it is not being used as a current carrying conductor.
One possible problem I did not realize before would be if the wiring began in a sub panel. In that cause there may be a current present if neutral wire fails between main and the sub panel.


Since the op's wiring has 3 conductors in a metallic conduit, I see 3 possible options.
1. Just cap neutral and use the junction box and conduit as an EGC.
2. Pull a new ground conductor (w/ green sheathing)
3. Repurpose neutral conductor as an EGC.

Option 1 and 3 is easiest and does not cost anything. But, the option 3 will be not code compliant because color of the wire is not green. In fact, it is illegal as is because blue wire is being repurposed as neutral conductor.


Has anyone confirmed existing wiring is 8 AWG?
To me that looks closer to 10 AWG.
 
  #24  
Old 03-20-17, 11:08 AM
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The issue you have is the ground - or lack thereof. You can not reidentify any conductor in a conduit, you must pull a new green one. We can't stop you from moving the white to the ground bar in the panel and taping it green at both ends, and there would be nothing "unsafe" about doing that... But just know that it is a code violation.
The ground issue is strictly the color of the wire and nothing more. Before pulling a new #10 green ground I'd consult the AHJ and ask if they would allow me to tape the third wire green at both ends. Absolutely no need to transfer the wire from neutral bus to ground bar. Odds are very great he has no ground bar anyway as a ground bar isn't required in the main panel. EGCs are terminated on grounded neutral bus.
 
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Old 03-20-17, 12:56 PM
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Agreed, and I'd give it about a 99% chance the inspector will allow the white-taped wire to be green-taped instead. It's not per-code, but inspectors allow this all the time in the field.
 
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Old 03-20-17, 04:28 PM
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Before pulling a new #10 green ground I'd consult the AHJ and ask if they would allow me to tape the third wire green at both ends.
You would seriously go through all that trouble to avoid pushing a dollar's worth of wire through 3 feet of pipe, and doing it the RIGHT way?????

Christ on a stick.
 
  #27  
Old 03-21-17, 11:19 AM
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Originally Posted by taz420
Ok excellent. That means it shouldnt be a problem. If it really is a straight drop, you MIGHT be able to thread the new ground wire in without pulling the old ones out. No promises, but its worth a try over that short a distance.
Thanks!
Left pic: Top arrow shows hole in wall, at back of panel, on opposite side of wall, which FWIW is a sub-panel not my main panel. Bottom arrow shows cooktop junction box location, under counter.
Right pic: Where both cooktop (red arrow) and range hood (blue arrows) wiring enter from panel. Cooktop (red arrow) has a non-flex metal piping, which does appear to drop right down to the junction box, under counter. Range hood may have to be addressed also and may be a bigger issue because it also appears to not have a ground AND is apparently sharing a breaker with the refrigerator.

FWIW: It's very helpful, knowing what will work and if an inspector may or may not approve. That said, one of my goals here to learn...Whether or not, I DIY a project or hire a pro, I want to learn the right way to do it.

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The wire you have is #10, so you can use that green. The size is indicated by the "AWG 10" printed on it.
The existing wiring appears thicker than the #10 I have but I can't read anything on exisitng so how can I tell, if my #10 matches it?

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  #28  
Old 03-21-17, 04:35 PM
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What you have existing is #6. With #8 and larger the ground can be smaller than the hot/neutral. #10 is the proper size for that circuit.

Now how do you figure that panel is a sub? Is there another panel with a 240V breaker that feeds it? Because if there is you have a MAJOR problem because subs require a separate ground and the grounds can not land on the neutral bar.......

Edit: I just noticed there is no main in there... How big is this house? Is there another panel? It could be that if this is the only panel, then upon initial installation could have complied with the "six throws" rule which means if there are 6 or less circuits (all circuits can be disconnected with six throws of the hand) a main is not required.. But I don't know. If that is indeed a sub, then it is actually dangerous.
 
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Old 03-21-17, 05:20 PM
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Because if there is you have a MAJOR problem because subs require a separate ground and the grounds can not land on the neutral bar.
Depends on when the sub was installed. It may be grandfathered.
 
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Old 03-21-17, 07:14 PM
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Originally Posted by taz420

What you have existing is #6. With #8 and larger the ground can be smaller than the hot/neutral. #10 is the proper size for that circuit.

Now how do you figure that panel is a sub? Is there another panel with a 240V breaker that feeds it? Because if there is you have a MAJOR problem because subs require a separate ground and the grounds can not land on the neutral bar.......

Edit: I just noticed there is no main in there... How big is this house? Is there another panel? It could be that if this is the only panel, then upon initial installation could have complied with the "six throws" rule which means if there are 6 or less circuits (all circuits can be disconnected with six throws of the hand) a main is not required.. But I don't know. If that is indeed a sub, then it is actually dangerous.
I know it's a sub-panel because yes, there's another panel with over 30 breakers, including a 240V breaker that feeds it. The house is 3100 sq ft.
 
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Old 03-21-17, 07:33 PM
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You would seriously go through all that trouble to avoid pushing a dollar's worth of wire through 3 feet of pipe, and doing it the RIGHT way?????
No, if I were doing it I probably wouldn't do any more than tape both ends green and be done with it, this is after all an existing house built to codes well before those of today. I am not there and haven't seen it and am not doing it and wouldn't give that advice to someone who wants to do it right without having looked at it first. The OP THINKS the conduit is only 3 or 4 feet between the panel and the box, but we don't know that for sure.
 
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Old 03-22-17, 09:19 AM
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Originally Posted by CasualJoe
...The OP THINKS the conduit is only 3 or 4 feet between the panel and the box, but we don't know that for sure.
Correct, after further review, I am unable to confirm that the cooktop conduit is a continuous run, unless I start tearing up the wall.
 
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Old 03-22-17, 06:38 PM
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Individual conductors should be in a complete conduit system. Can you try a fish tape between boxes? Maybe blow air into one end and see if someone can feel it at the other.
 
  #34  
Old 03-23-17, 02:25 PM
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Depends on when the sub was installed. It may be grandfathered.
1. You have not been allowed to combine neutrals and grounds after the SE since 1923 (with the exception of 3 wire appliances up until 1996). The circuit breaker was invented in 1934. That panel was probably installed in the 60s or 70s.

2. That neutral bar is probably bonded, AND the panel is fed via conduit, providing a potential return path. It is dangerous and never met code. Period.

No, if I were doing it I probably wouldn't do any more than tape both ends green and be done with it, this is after all an existing house built to codes well before those of today.
See #1 and #2 above.

The OP THINKS the conduit is only 3 or 4 feet between the panel and the box, but we don't know that for sure.
Its 3 feet below the panel on the opposite side of the wall with no other conductors coming out of either end. You seriously believe it goes somewhere else? I have a bridge for sale...
 
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Old 03-25-17, 09:47 AM
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Originally Posted by pcboss

Individual conductors should be in a complete conduit system. Can you try a fish tape between boxes? Maybe blow air into one end and see if someone can feel it at the other.
Thanks!
Fish tape, huh? Since it's just me, who'd being blowing air, that sounds interesting. What length is recommended for homeowner/DIYer to buy and have on hand? Steel or fiberglass?
 
  #36  
Old 03-25-17, 03:12 PM
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A 50' would be fine for you. Fiberglass is round so its not going to snag as easily on existing wires in the conduit.

But as I said, the possibility that you don't have a continuous run on that short of a distance is infinitesimal. You will very likely be able to just push that #10 green through from the panel end.

Now back to the panel issue.. Can you post a clear closeup of the neutral bar please? We need to make sure that it is not bonded. You will also need to remove those green wires from the neutral bar and install a separate ground bar (or at the very least, drill a hole in the back of the panel, scrape the paint to bare metal, and install a #10 pigtail with a self-tapping screw).
 
  #37  
Old 03-25-17, 06:16 PM
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Thanks!
50' fiberglass. You're probably right about the continuous run. That said, the area, I thought the cooktop conduit was coming out of the back of the panel; is not the correct because it comes out of the bottom NOT the back and I have not been able to see it or feel it, from inside the kitchen.

As for the panel neutral bar, I assume you mean this...
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  #38  
Old 03-25-17, 06:29 PM
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Hmm.. Ok.. I don't see a bonding screw, but I also don't see a place for one unless it's related to that silver stud/black dot in the upper left above the bars above the insulator. Can you post the brand/part number of the panel? That will be on the door sticker.


Now I see another potential issue..

What are the ratings of those two red breakers upper left? Those two circuits are double-lugged (illegal unless the breakers are rated for two wires, unlikely that those are) and the wires appear to be two different sizes. If the breaker is say, 20A and the wires are #10 and #12, then it's not a safety problem, but if it's 20A and the wires are #12 and #14, then it's dangerous. Are there any markings on the smaller (red and black) wires?

Sorry this is becoming a can of worms, but we're kind of obligated to point out safety issues.

I could tell the conduit to the cooktop box was in the bottom, which is why I said in the first place that you could probably stick the new ground right through. Based on where those other two circuits you pointed out in the wide picture come out, it looks to be straight down from the panel.

It appears that there is only one conduit coming out of the top of the panel. It really wouldn't be difficult to replace that panel with one slightly larger and less rusty. One that you can get breakers and a ground bar for, and has enough circuit capacity to eliminate the double lugged circuits (it appears that there is one more on the other side now that I look closer) and the tandem breaker.
 

Last edited by taz420; 03-25-17 at 06:46 PM.
  #39  
Old 03-25-17, 09:33 PM
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Any time you post a pic everyone loves finding problems. What's with the white tape on black/blue wires? Normally only allowed on 4 gauge and larger.
 
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Old 03-25-17, 09:56 PM
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What's with the white tape on black/blue wires? Normally only allowed on 4 gauge and larger.
Yeah that horse has already been beaten to death in this thread...
 
 

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