Preparing for Infrastructure Lapses... - Page 6

oil pan 4 · 11-30-14, 03:21 AM

I wouldn't use a relay. A set of contacts could stick. This is why we don't rely on something like a relay to protect people working on a high powered system. With backup power think of linemen trying to repair power lines, they are depending on you disconnecting from the main power source.
In industry stuff like this calls for something that creates a wide air gap for a safe and proper isolation from the power source. So in industry something like that needs an actual disconnect switch that you can put a lock on is called for.

jeff5may · 11-30-14, 10:20 AM

oil pan,

What I'm saying here is that residential electrical codes in general have different standards than I/C installations, due to the average knowledge level of common citizens, and the lack of formal procedures (and sufficient insurance and emergency response) in the residence. You seem to think that since you can inspect and approve your own commercial work, you can do so without a permit or inspection at home. This is incorrect: by approving and implementing your own changes, you are bypassing part of the process and assuming civil liability for your actions.

I'm not trying to insult you. I understand you have a high level of skill and knowledge. But if a meter reader comes around while you have your power meter pulled, with a broken (or no) seal on the box, he's not going to inform you. He's just going to report the occurrence.

This may or may not generate a house call and trouble for you. You may just get a letter in the mail with a fine attached. Then again, no one might care. You might get away with it, you might not. But why put yourself in that situation willingly?

This leads to the "Jurassic park" question. Just because you know what you're doing, and that it will work, doesn't always mean that you should. The codes and inspection standards have been put in place to protect you (and others) from yourself.

If something goes wrong while your "rogue" system is operating, what will happen? I don't know. But if something bad happens, you could get caught in a situation with your pants down. Authority figures in general tend to judge against gamblers when they have to make a decision. You may not get a chance to pull your pants up with dignity. The ruling handed to you may be more than you can stomach.

Again, I'm not trying to attack you personally. You may be comfortable assuming the risk and liability involved with the decisions you are making. What I'm saying is that your methods are not appropriate for everyone. Encouraging others to carbon copy what you did on an open forum invites disaster for someone who lacks full understanding of what you did.

NiHaoMike · 11-30-14, 12:31 PM

Quote:

Originally Posted by oil pan 4

I wouldn't use a relay. A set of contacts could stick. This is why we don't rely on something like a relay to protect people working on a high powered system. With backup power think of linemen trying to repair power lines, they are depending on you disconnecting from the main power source.
In industry stuff like this calls for something that creates a wide air gap for a safe and proper isolation from the power source. So in industry something like that needs an actual disconnect switch that you can put a lock on is called for.

The "relay" would actually be more like a heavy duty contactor, except it would be one that has NC contacts in addition to NO contacts. If it jams for any reason, it simply won't switch over. (It is also noted that most UPSes use a DPDT relay to engage bypass mode.) You can also use a pair of interlocked contactors often used to reverse 3 phase motors, although the standby loss would be significant.

oil pan 4 · 11-30-14, 02:35 PM

UPS are not covered by NEC. They fall under equipment.

Quote:

Originally Posted by jeff5may

assuming civil liability for your actions.

Noting new about that.

Quote:

Originally Posted by jeff5may

If something goes wrong while your "rogue" system is operating, what will happen?

With a 4 inch air gap between the homes power system and the power grid and with the generator out put on a breaker plus where it comes into the panel also on a breaker. The only possibility is a breaker will flip.

gtojohn · 12-06-14, 09:18 AM

Quote:

Originally Posted by NiHaoMike

What about using a small CHP generator as a primary heat source (backup if you have solar or other alternative heat source) as well as a backup/auxiliary power source? A DPDT relay can be used to switch certain loads to generator whenever it's running regardless of the status of the mains power.

My solar guy advised against mixing the generators and solar. His reasoning was generators are somewhat dirty power, and phasing between power sources, as well as risk to an expensive solar system.

My original idea was bring in some generator only outlets near relevant areas and plug in appliances as needed. That would solve dangers and operator problems as well as let you know when utility power is restored

NiHaoMike · 12-06-14, 10:43 AM

Solar and generators coexist just fine if you know what you're doing. The off griders do that a lot.

oil pan 4 · 12-06-14, 12:21 PM

Quote:

Originally Posted by gtojohn

My solar guy advised against mixing the generators and solar. His reasoning was generators are somewhat dirty power, and phasing between power sources, as well as risk to an expensive solar system.

My original idea was bring in some generator only outlets near relevant areas and plug in appliances as needed. That would solve dangers and operator problems as well as let you know when utility power is restored

If you are running off grid solar you have to have a backup generator.
If you run grid tie you have to isolate and basically lock out the solar before powering up with the generator.

gtojohn · 12-07-14, 12:23 PM

My solar would be gridtie hence the advisement. For the most part off grid you are running off batteries and charging batteries by various means.

NiHaoMike · 12-07-14, 10:05 PM

How about add in the ability to use it as an off grid setup when needed? It could be as simple as making the DC input easily accessible and connecting a DC/DC converter when needed.

oil pan 4 · 12-09-14, 07:07 PM

I have read up on the latest code for generator transfer switches and its completely idiotic.

In a nut shell there are 2 way to do it.
In one you wire your main panel through the generator transfer switch, running power through your generator transfer switch all the time then back to the main panel to power certain circuits. These select circuits are wired on numerous little on-off-on switches and are the only ones that can be powered by the generator.
This would work great if you had a 3 phase generator, actually it would be the only way to a 3 phase generator into a single phase house. If I had a 3 phase generator I would use this my self. (but then you end up with 208 volts running on your 240 volt circuits, not that big of a problem) This would also allow you to use a tiny single line 120 volt generator to power your house, which wouldn't really run crap.

The other way you wire in a generator panel up is you tie a subpanel into your main. Then in this sub panel you use a two breakers as a transfer switch. You use a 60 amp breaker in your transfer subpanel to use as "a grid disconnect" installed directly across from a your 30 amp generator breaker and use a very easy to remove "lock out linking bar" to make sure both cant be turned on at the same time. That works great as long as some one doesn't see that there is a breaker cant be turned on and gets the bright idea to remove the bar and turn everything on.
I don't like that method for 2 reasons:
Like with the generator transfer panel only circuits wired on this special subpanel can be powered with the generator.
It uses simple breakers for grid disconnect which I do not like. I like actual disconnect switches that put a big air gap between you and disaster.

I could easily wire up these types of generator tie ins, for some one else. Its quite simple.

Both are just idiot proofing for people who understand nothing about electricity to prevent them from turning everything in their house on at the same time while using generator power.
I am well aware I cant run everything at the same time with a 30 amp 240 volt generator but need the option to run what ever I want.

If you are going to wire it up so that ultimately you can only run a few circuits with your transfer switch you might as well save your self a few thousands dollars and run extension cords everywhere that you need power when the power goes out.

In our next house I will wire in a big on-off-on disconnect switch to the main so I can run any circuit.
My giant on-off-on switch that powers everything is still used, just not very often because the 2 other ways are said to be cheaper. Which I don't see how.

11-30-14, 10:20 AM	#52
jeff5may Supreme EcoRenovator Join Date: Jan 2010 Location: elizabethtown, ky, USA Posts: 2,428 Thanks: 431 Thanked 619 Times in 517 Posts	even pirates keep to the code oil pan, What I'm saying here is that residential electrical codes in general have different standards than I/C installations, due to the average knowledge level of common citizens, and the lack of formal procedures (and sufficient insurance and emergency response) in the residence. You seem to think that since you can inspect and approve your own commercial work, you can do so without a permit or inspection at home. This is incorrect: by approving and implementing your own changes, you are bypassing part of the process and assuming civil liability for your actions. I'm not trying to insult you. I understand you have a high level of skill and knowledge. But if a meter reader comes around while you have your power meter pulled, with a broken (or no) seal on the box, he's not going to inform you. He's just going to report the occurrence. This may or may not generate a house call and trouble for you. You may just get a letter in the mail with a fine attached. Then again, no one might care. You might get away with it, you might not. But why put yourself in that situation willingly? This leads to the "Jurassic park" question. Just because you know what you're doing, and that it will work, doesn't always mean that you should. The codes and inspection standards have been put in place to protect you (and others) from yourself. If something goes wrong while your "rogue" system is operating, what will happen? I don't know. But if something bad happens, you could get caught in a situation with your pants down. Authority figures in general tend to judge against gamblers when they have to make a decision. You may not get a chance to pull your pants up with dignity. The ruling handed to you may be more than you can stomach. Again, I'm not trying to attack you personally. You may be comfortable assuming the risk and liability involved with the decisions you are making. What I'm saying is that your methods are not appropriate for everyone. Encouraging others to carbon copy what you did on an open forum invites disaster for someone who lacks full understanding of what you did.

12-06-14, 10:43 AM	#56
NiHaoMike Supreme EcoRenovator Join Date: Oct 2008 Location: Austin, TX Posts: 1,154 Thanks: 14 Thanked 257 Times in 241 Posts	Solar and generators coexist just fine if you know what you're doing. The off griders do that a lot. __________________ To my surprise, shortly after Naomi Wu gave me a bit of fame for making good use of solar power, Allie Moore got really jealous of her...

12-07-14, 10:05 PM	#59
NiHaoMike Supreme EcoRenovator Join Date: Oct 2008 Location: Austin, TX Posts: 1,154 Thanks: 14 Thanked 257 Times in 241 Posts	How about add in the ability to use it as an off grid setup when needed? It could be as simple as making the DC input easily accessible and connecting a DC/DC converter when needed. __________________ To my surprise, shortly after Naomi Wu gave me a bit of fame for making good use of solar power, Allie Moore got really jealous of her...

11-30-14, 03:21 AM	#51
oil pan 4 Land owner Join Date: Nov 2012 Location: NM Posts: 1,026 Thanks: 12 Thanked 127 Times in 107 Posts	I wouldn't use a relay. A set of contacts could stick. This is why we don't rely on something like a relay to protect people working on a high powered system. With backup power think of linemen trying to repair power lines, they are depending on you disconnecting from the main power source. In industry stuff like this calls for something that creates a wide air gap for a safe and proper isolation from the power source. So in industry something like that needs an actual disconnect switch that you can put a lock on is called for.

12-07-14, 12:23 PM	#58
gtojohn Journeyman EcoRenovator Join Date: Jul 2014 Location: Austin, TX Posts: 314 Thanks: 39 Thanked 50 Times in 45 Posts	My solar would be gridtie hence the advisement. For the most part off grid you are running off batteries and charging batteries by various means.

12-09-14, 07:07 PM	#60
oil pan 4 Land owner Join Date: Nov 2012 Location: NM Posts: 1,026 Thanks: 12 Thanked 127 Times in 107 Posts	I have read up on the latest code for generator transfer switches and its completely idiotic. In a nut shell there are 2 way to do it. In one you wire your main panel through the generator transfer switch, running power through your generator transfer switch all the time then back to the main panel to power certain circuits. These select circuits are wired on numerous little on-off-on switches and are the only ones that can be powered by the generator. This would work great if you had a 3 phase generator, actually it would be the only way to a 3 phase generator into a single phase house. If I had a 3 phase generator I would use this my self. (but then you end up with 208 volts running on your 240 volt circuits, not that big of a problem) This would also allow you to use a tiny single line 120 volt generator to power your house, which wouldn't really run crap. The other way you wire in a generator panel up is you tie a subpanel into your main. Then in this sub panel you use a two breakers as a transfer switch. You use a 60 amp breaker in your transfer subpanel to use as "a grid disconnect" installed directly across from a your 30 amp generator breaker and use a very easy to remove "lock out linking bar" to make sure both cant be turned on at the same time. That works great as long as some one doesn't see that there is a breaker cant be turned on and gets the bright idea to remove the bar and turn everything on. I don't like that method for 2 reasons: Like with the generator transfer panel only circuits wired on this special subpanel can be powered with the generator. It uses simple breakers for grid disconnect which I do not like. I like actual disconnect switches that put a big air gap between you and disaster. I could easily wire up these types of generator tie ins, for some one else. Its quite simple. Both are just idiot proofing for people who understand nothing about electricity to prevent them from turning everything in their house on at the same time while using generator power. I am well aware I cant run everything at the same time with a 30 amp 240 volt generator but need the option to run what ever I want. If you are going to wire it up so that ultimately you can only run a few circuits with your transfer switch you might as well save your self a few thousands dollars and run extension cords everywhere that you need power when the power goes out. In our next house I will wire in a big on-off-on disconnect switch to the main so I can run any circuit. My giant on-off-on switch that powers everything is still used, just not very often because the 2 other ways are said to be cheaper. Which I don't see how.