As was stated, it's NEC code for over 60 Amps (I believe) installations. Your jurisdiction and/or inspection may or may not require/care. A lockout on the circuit breaker may be sufficient also if nearby.
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HankLloydRight
No Roads
mknox
Well-Known Member
I have done this. I bought a NEMA 14-50 plug and pigtail at Home Depot that is intended to be wired into an electric range. I didn't bother cutting it down to 12" because it already had nicely installed terminals on it. I think it is probably 24" long at most.
Kind of a strange one here... curious if our electrician friends have any insight.
We had some crazy high winds the other night where I live, and that sometimes leads to power outages. In this case, however, there appeared to a sizable power surge. The kind that makes a power strip go POP (sounded like a big light bulb exploding). The power went out for a few seconds, then cycled back on... then off again. Then back on, and stayed on. Whole event lasted about a minute.
BUT... lots of breakers tripped. I went about resetting stuff, but some things seemed fried. Specifically, the power to my thermostat on my main forced HVAC unit... off. Possibly the transformed got fried? Guy coming out in a couple of days to check on that one... same deal for a ductless HVAC unit... no power.
The big one, though, was the HPWC. That one is on a subpanel. The breaker to the subpanel tripped. And a bunch of breakers on the subpanel itself tripped, including the dedicated breaker for the HPWC. I was able to reset all of them but that breaker, which would not return to the ON position (yeah, I moved it to OFF first).
In the morning, when I took a better look at it, I saw that the plastic cover of the HPWC was actually pushed off of the unit in the top corner... and you could see char marks. Basically, it was fried... and did so with enough force that the cover was actually blown out a bit.
The electricians are installing a replacement right now. The breaker for the HPWC is officially toast. Their working theory is... big spike in voltage goes through the breaker, hits the HPWC, there's a short in there, and it feeds power back into the breaker and fries it?
I'm an electricity idiot, so I'm probably using a bunch of incorrect terms and ideas. We're obviously replacing the unit and breaker, so we should be back up and running soon... but curious... what exactly happened here? And is there any way to protect against such an occurrence again?
We had some crazy high winds the other night where I live, and that sometimes leads to power outages. In this case, however, there appeared to a sizable power surge. The kind that makes a power strip go POP (sounded like a big light bulb exploding). The power went out for a few seconds, then cycled back on... then off again. Then back on, and stayed on. Whole event lasted about a minute.
BUT... lots of breakers tripped. I went about resetting stuff, but some things seemed fried. Specifically, the power to my thermostat on my main forced HVAC unit... off. Possibly the transformed got fried? Guy coming out in a couple of days to check on that one... same deal for a ductless HVAC unit... no power.
The big one, though, was the HPWC. That one is on a subpanel. The breaker to the subpanel tripped. And a bunch of breakers on the subpanel itself tripped, including the dedicated breaker for the HPWC. I was able to reset all of them but that breaker, which would not return to the ON position (yeah, I moved it to OFF first).
In the morning, when I took a better look at it, I saw that the plastic cover of the HPWC was actually pushed off of the unit in the top corner... and you could see char marks. Basically, it was fried... and did so with enough force that the cover was actually blown out a bit.
The electricians are installing a replacement right now. The breaker for the HPWC is officially toast. Their working theory is... big spike in voltage goes through the breaker, hits the HPWC, there's a short in there, and it feeds power back into the breaker and fries it?
I'm an electricity idiot, so I'm probably using a bunch of incorrect terms and ideas. We're obviously replacing the unit and breaker, so we should be back up and running soon... but curious... what exactly happened here? And is there any way to protect against such an occurrence again?
davewill
Active Member
If you can post of photo of the insides of the blown HPWC, we could guess better. My money is either on the power supply for the electronics, or the contactors themselves. As far as preventing it again, someone more knowledgeable than I will have to chime in.
Lightning strike, or maybe a short in a high transmission outside. Install a whole house surge protector, and also make sure your grounding rod is working and is deep enough.
Wow. Nasty. Further upstream root cause could have been source equipment cutting in out of phase, which near by transformers would hate? Beats me.
We put in sub panel level surge protectors on each of the two 200 amp sub panels. Don't know if its snake oil or if it would have helped or not. But it's a thing.
We put in sub panel level surge protectors on each of the two 200 amp sub panels. Don't know if its snake oil or if it would have helped or not. But it's a thing.
I've always wondered about this... How useful are whole house surge protectors? Would they protect expensive gadgets (like HPWCs, TVs, and others)? Would they have any side-effect? (Affect PowerLine networking perhaps?) Don't want to derail the thread, but protecting our $500-1100 (if you have two) investment in HPWCs would be useful!
DMC-Orangeville
Audi eTron & John Deere 5100E
They won't protect against a direct strike, but anything else they'll help with. There is no side effect.
Excellent! Does look like a good idea based on that and the info in the other thread.
I had a Leviton whole-house surge protector at my last home. I never had any surge issues (although maybe I just didn't have any surges!), and it didn't impact X10, Insteon, or Enphase's PLC comms between my Enphase hub and micro inverters. I plan to install one at my new house.
Any protection that does not protect from direct lightning strikes is best considered a scam. That is what effective protection has done for well over 100 years - protect from surges including direct lightning strikes.
Your telco's switching computer suffers about 100 surges with each storm. How often is your town without phone service for four days while they replace that switching computer? Never? Exactly. Protection from direct strikes is routine. And costs tens of times less than near zero joule (magic box) protectors.
Should lightning cause damage to any appliance, then a homeowner begins an investigation to discover his mistake. Start with THE most critical item in every protection 'system' - single point earth ground. A protector is only as effective as its earth ground. As explained elsewhere, that is where hundreds of thousands of joules harmlessly dissipate. Also explains why a connection from a protector to earth must be low impedance (ie less than 10 feet). And why all four words have electrical significance: single point earth ground.
BTW, the 'whole house' solution is only a 'secondary' protection layer. Informed homeowners also inspect their 'primary' protection layer. Each layer is never defined by a protector. Each layer is defined by the item that can absorb hundreds of thousands of joules - earth ground.
Ignore text. View relevant pictures about half way down and after the expression "more safety hazards" in FPL Fraud. Those pictures demonstrate a 'primary' surge protection layer. Copper thieves can subvert that - your surge protection. Because protection is always about and defined by a connection to and quality of the earth ground. A protector is only as effective as its earth ground. It explains why plug-in protectors do not even claim to protect from potentially destructive surges.
We must have different definitions of "direct lightning strike." The one I saw blew out multiple electronics, melted feeders, and started a fire. Nothing would have prevented that damage.
Did you first learn numbers? Lightning currents did not do that damage. When lightning is not properly and safely connected to earth, then something with massive more energy causes that damage. Learn about a "follow through current". That (and not lightning) has sufficient energy - explains that damage.
A conclusion made without first learning fundamental concepts is called junk science. Once that observation is combined with well understood knowledge (of a 'follow through current' and why it can happen), then the same observation results in a completely different conclusion. Junk science was originally explained in elementary school science.
"Did I learn numbers" and "junk science"? Seriously? I thought we were gearing up for an interesting lightning discussion, but if you're going to go right to BS ad hominem insults, you just earned the first slot on my ignore list.
That could happen if conclusions were not speculated only using observation. With knowledge based in numbers, then lightning clearly did not melt that feeder and start a fire. Lightning has insufficient energy. If not properly earthing effective protection, then a follow through current explains that damage - as previously explained.
Incendiary phrases such as BS and ad hominem insults says one only wants to argue. Defects in your reasoning and resulting conclusions were precisely targeted. Conclusions based only in observation are classic junk science - as first taught in elementary school science. Ask to learn the science rather than make accusations and conclusions based only in observation, speculation, and emotion.
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