Reduced neutral to dryer

[electrofelon]

nah, no need for logical grams. 3ph with modern day controls may present some harmonics issues. its way beyond this forum to dig into, but at least now you know.

Yes harmonics are way above this forum. No one on here understands them. Keep that topic in your smart people electrical forum - if you have time after your "ridiculous what ifs forum" postings.

 

[FionaZuppa]

No one. But people in pottery, craft and hobby forums will routinely ask and talk about plunging their Ebay Kiln (look at the cord)
into a dryer outlet.

yes, understood. for OP it doesnt matter, for std resi, it perhaps matters.
but again, having a 14-50 NEMA and say a 30A ocpd with all #10 may still pose an issue if the kiln needs 40A, so swapping 30 for 40 ocpd puts it right into danger zone. hazards beyond that around a downsized N has real possibility.

but heck, maybe just a sticker on cover plate would solve this snafu :lol::lol:

 

[FionaZuppa]

Yes harmonics are way above this forum. No one on here understands them. Keep that topic in your smart people electrical forum - if you have time after your "ridiculous what ifs forum" postings.

well, where's iwire to fork this off into a "harmonics" topic where you can help us understand how harmonics generated by modern day controls could affect the N wire on a 3ph piece of equipment. i'll just bow out of that discussion.

 

[iwire]

The receptacle. A load with a NEMA 14-50 will not pull more than 50amps. A short circuit would still trip the breaker in theory since its no different than a motor application where a 50amp breaker can protect #12.


In the case of the dryer we have a scenario where nothing will protect the neutral from over load be it breaker or cord cap.

Wow, you seem to have your head buried in the sand.

Potential 10 ampsp overload unsafe, 50 amp overload fine. Really not following that logic.

 

[FionaZuppa]

Wow, you seem to have your head buried in the sand.

Potential 10 ampsp overload unsafe, 50 amp overload fine. Really not following that logic.

i think he means, a full short to N would quickly trip the 50A ocpd, thus the 50ocpd still protected the #12. a heavy load on the #12 N would not.

 

[iwire]

Topic split by request http://forums.mikeholt.com/showthread.php?t=181100

 

[mbrooke]

Wow, you seem to have your head buried in the sand.

Potential 10 ampsp overload unsafe, 50 amp overload fine. Really not following that logic.

So you are saying the NEC is wrong about motor short circuit and ground fault protection?

 

[Fulthrotl]

What other people do with my installations is of no concern to me whatsoever. Please stop trying to put your theoretical "what ifs" into real world situations, you have no practical experience as an electrician and shouldn't be lecturing us on what should and shouldn't be done.

.
peter, go out to the truck, get a damn spool of #10 wire,
pull it in, make it up, and let's move along. ok?

the delta is about $2 between the wire costs, divided
by the 100 posts here picking flys***t out of pepper, so that
makes each post pro rated at $0.02.

this is my $0.02 worth.

 

[iwire]

So you are saying the NEC is wrong about motor short circuit and ground fault protection?

No, I was talking about welders and the receptacles that feed them.

You do know it is a violation to plug say a 50 amp rated stove into a 50 amp outlet protected by a 100 right?

 

[mbrooke]

No, I was talking about welders and the receptacles that feed them.

You do know it is a violation to plug say a 50 amp rated stove into a 50 amp outlet protected by a 100 right?

I do. But what will happen in reality? How great is the risk? Who will add extra heating coils to that stove? I may not have overload protection, but I still have short circuit protection.

 

[iwire]

I do. But what will happen in reality? How great is the risk? Who will add extra heating coils to that stove? I may not have overload protection, but I still have short circuit protection.

Exactly and how is that different in the least from the dryer example?

You are just being very selective in your worries, I think that is unwarranted and really does not make much sense.

In my example doubling the allowable current seems like it could be a safety issue. In the case of the dryer at worst we can only load the neutral a few amps over its stated rating? Not seeing the danger.

Of course I forgetting to consider all that harmonic current loading caused by the digital timer .... :lol::lol:

 

[mbrooke]

Exactly and how is that different in the least from the dryer example?

The dryer example is a sustained chronic overload possibly going on for years. The welder/stove scenario is not.

You are just being very selective in your worries, I think that is unwarranted and really does not make much sense.

It makes sense to the CMPs. They make this decision countless times every 3 years.

In my example doubling the allowable current seems like it could be a safety issue. In the case of the dryer at worst we can only load the neutral a few amps over its stated rating? Not seeing the danger.

I am not denying this, but a resi stove will not place 90 amps on a circuit no matter how much you wish it will.

Of course I forgetting to consider all that harmonic current loading caused by the digital timer .... :lol::lol:

Fiona was wrong here.

 

[iwire]

The dryer example is a sustained chronic overload possibly going on for years. The welder/stove scenario is not.

No, the dryer will not overload the neutral. Maybe the kiln someone plugs into it.

It makes sense to the CMPs. They make this decision countless times every 3 years.

No facts in evidence to support this.

I am not denying this, but a resi stove will not place 90 amps on a circuit no matter how much you wish it will.

No, but it is the same deal, you do not know what will be plugged into either my imaginary welder outlet or a dryer outlet. You are getting all worried about a 5 amp overload on a 25 amp conductor but are unconcerned about a 50 amp overload on a 50 amp conductor.


Now to be clear, IMO it is all moot as 240.4(B) prevents what the OP was suggesting.

 

[mbrooke]

No, the dryer will not overload the neutral. Maybe the kiln someone plugs into it.

Thats my point. A Kiln would with #12. Someone plugging a stove or NEMA 14-50p device into a NEMA 14-50r protected by a 100amp breaker will not. The reason being that a 30amp plug can legally draw 30amps and a 50amp plug can legally draw 50amps. In the dryer scenario the circuit can not handle 30amps, in the welder it can.

No facts in evidence to support this.

:lol::roll: The entire NEC is based on risk assessment and balance.

No, but it is the same deal, you do not know what will be plugged into either my imaginary welder outlet or a dryer outlet. You are getting all worried about a 5 amp overload on a 25 amp conductor but are unconcerned about a 50 amp overload on a 50 amp conductor.

I think you refuse to see that a device that comes with a factory fitted 50amp plug will not pull more than 50amps.

Now to be clear, IMO it is all moot as 240.4(B) prevents what the OP was suggesting.

I agree and I believe your interpretation of the code is bar-none, however I am adding a technical reason why the code might be forbidding this.

 

[kwired]

yes, understood. for OP it doesnt matter, for std resi, it perhaps matters.
but again, having a 14-50 NEMA and say a 30A ocpd with all #10 may still pose an issue if the kiln needs 40A, so swapping 30 for 40 ocpd puts it right into danger zone. hazards beyond that around a downsized N has real possibility.

but heck, maybe just a sticker on cover plate would solve this snafu :lol::lol:

Warning labels solve everything. Nobody reads them for the most part, but it still helps relieve any liability on the person that placed the label.

.
peter, go out to the truck, get a damn spool of #10 wire,
pull it in, make it up, and let's move along. ok?

the delta is about $2 between the wire costs, divided
by the 100 posts here picking flys***t out of pepper, so that
makes each post pro rated at $0.02.

this is my $0.02 worth.

If I were in that situation there likely isn't an #10 white on the truck to grab. I generally only have 10 white along when I know I will be needing it, which doesn't seem to be that often. I usually do have 10 green and black on the truck at all times.

 

[FionaZuppa]

Warning labels solve everything. Nobody reads them for the most part, but it still helps relieve any liability on the person that placed the label.

If I were in that situation there likely isn't an #10 white on the truck to grab. I generally only have 10 white along when I know I will be needing it, which doesn't seem to be that often. I usually do have 10 green and black on the truck at all times.

right, tiny cover plate stickers, a lawyers solution for a hazard, got it.:thumbsup:

you not having white available for the job your are about to do? who's fault is that?

 

[kwired]

right, tiny cover plate stickers, a lawyers solution for a hazard, got it.:thumbsup:

you not having white available for the job your are about to do? who's fault is that?

My fault. Also my judgement as to whether I want to risk using 12 or white taping something else, especially if no inspector is going to look at it. I probably will do one or the other instead of driving 20 miles to the shop and 20 miles back just to get 30 feet of 10 AWG wire, if that is all there is holding up completing the job.

 

[FionaZuppa]

My fault. Also my judgement as to whether I want to risk using 12 or white taping something else, especially if no inspector is going to look at it. I probably will do one or the other instead of driving 20 miles to the shop and 20 miles back just to get 30 feet of 10 AWG wire, if that is all there is holding up completing the job.

hold up. you gonna risk it? what about the cust, what risk do you give them by "risking it".
your heavy rig gets about ~15mpg hwy, 40mi, thats ~2.6gal, lets say diesel at $3.25/gal, so for $8.45 and ~1hr wasted in drive time, you opt to "risk it".
sure, ok, i guess that is REAL WORLD from an electrician's view, got it :thumbsup:

 

[ActionDave]

hold up. you gonna risk it? what about the cust, what risk do you give them by "risking it".
your heavy rig gets about ~15mpg hwy, 40mi, thats ~2.6gal, lets say diesel at $3.25/gal, so for $8.45 and ~1hr wasted in drive time, you opt to "risk it".
sure, ok, i guess that is REAL WORLD from an electrician's view, got it :thumbsup:

How much different is it from your real world antics in your thread here? Seems you were unwilling to go to any extra effort at all and saved about twelve cents of wire.
http://forums.mikeholt.com/newreply.php?do=newreply&p=1617889

i forgot to mention, i have no wall box for a switch, the controllers themselves are the on/off device. its basically 20A gfi from panel out to a outdoor kitchen which feeds the ceiling fans via single 14/2....

Do I understand you that you have a 20 amp circuit with 14 gauge switch leg? I t also seems like you have one switch leg for all the fans, yes?

well, not exactly.
20a gfi breaker in main panel, 12/2 runs out ~100ft to a junction box, from there 14/2 feeds all the fans (wireless controller is the "switch" for the fans, etc). this is how it was submitted for permit, and was approved...

14 is easier to pull, less $$.
but i can switch to 12. using the 75C column derating the 14 wire does fall below 20a breaker.

ok, NEC aside, whats the hazard in this specific case?

the 240.4(G) examples are showing 40a breaker with 14 wire...... seems odd to me.


from NEC


a ceiling fan kinda fits in, no?? they are built typically to std sizes, perform function of circulating air and in some cases provide lighting. of the weak examples in the definition a ceiling fan seems closest to air-conditioning.

...Fiona, I am not sure what is going on but you don't seem to want to understand the code but rather you seem to want to make your case work. It is not compliant-- what else can I say- maybe someone else will chime in- you wore me out...:lol:

 

[kwired]

hold up. you gonna risk it? what about the cust, what risk do you give them by "risking it".
your heavy rig gets about ~15mpg hwy, 40mi, thats ~2.6gal, lets say diesel at $3.25/gal, so for $8.45 and ~1hr wasted in drive time, you opt to "risk it".
sure, ok, i guess that is REAL WORLD from an electrician's view, got it :thumbsup:

Knowing darn well that neutral will likely never see more then 10 amps, you are darn right I would. If that one in a billion chance hits me - I have insurance for a reason, I also probably should start playing the lottery if my odds are that good.