Hypothetical-Table 310.15(B)(6)

[jetlag]

Nope, I don't buy it and you didn't answer my question about the fusible switch.

Roger

Remember how many years and how many house fires before they finally made the old scew in boxes so a 30 amp could not be installed in the 15 or 20 amp socket ? It does not help the people that went to their grave to call them stupid . They might have been doctors or lawyers . We are suppose to protect those people . Just like they protect us when we need them .

 

[George Stolz]

Any way I dont believe the lugs on the first 200 panel would be rated for 400 amp.

I don't believe I've ever seen an ampacity shown on a lug. Can you provide an example?

I don't see where this is allowed in 230.82.

I don't see how that is relevant; 230.82 does not forbid service raceways from being on the line side of the service disconnect, which is what is described.

Another question I have is the location of the first disconnect. Where is the neutral and grounding electrode system bonded?

I imagine it would be the same as any other pair of service disconnects. There are a number of ways to do it, and the grounding/bonding of the service doesn't seem relevant to the discussion, no?

Consider the post Bob made about a marina getting sued over a fatality because they did not exceed the NEC requirements for GFCI protection.

An attorney will beat you on this in court if someone dies in a fire...

This is a question of code compliance, I recommend we keep it as such. Guessing as to how a fictional trial would play out does not help us come to the answer of the original question, which is whether the installation described is in violation of the NEC or not. Let's draw the line there.

 

[Dennis Alwon]

Remember how many years and how many house fires before they finally made the old scew in boxes so a 30 amp could not be installed in the 15 or 20 amp socket ? It does not help the people that went to their grave to call them stupid . They might have been doctors or lawyers . We are suppose to protect those people . Just like they protect us when we need them .

Jetlag, do you have statistics for this comment. I beg to differ. I truly believe there are very few house fires due to wiring. Also I would bet that a 30 amp fuse on a #12 wire would likely, in time, fray the insulation and short out but not cause a wire-- the old knob & tube would probably fair better yet.

 

[jetlag]

I don't believe I've ever seen an ampacity shown on a lug. Can you provide an example?


I don't see how that is relevant; 230.82 does not forbid service raceways from being on the line side of the service disconnect, which is what is described.



I imagine it would be the same as any other pair of service disconnects. There are a number of ways to do it, and the grounding/bonding of the service doesn't seem relevant to the discussion, no?




This is a question of code compliance, I recommend we keep it as such. Guessing as to how a fictional trial would play out does not help us come to the answer of the original question, which is whether the installation described is in violation of the NEC or not. Let's draw the line there.

Untill it is proven to me otherwise , I assume a panels lugs have the same rating as the panel box . As far as OP violation , there is no code violation , there I said it :grin:

 

[George Stolz]

Untill it is proven to me otherwise , I assume a panels lugs have the same rating as the panel box.

Take a look at the Ilsco site pertaining to distribution blocks and look for an ampacity on the chart, that should be good enough. Terminals are rated according to temperature, according to 110.14(C).

All the terminals on the sheet linked to are 90?.

 

[roger]

Remember how many years and how many house fires before they finally made the old scew in boxes so a 30 amp could not be installed in the 15 or 20 amp socket ?

And the point is?

It does not help the people that went to their grave to call them stupid .

No it doesn't but it may accurately describe them.

They might have been doctors or lawyers . We are suppose to protect those people .

And we have a set of rules to go buy to do just that

Just like they protect us when we need them .

Sorry but you could have probably picked a couple of better examples, the two you bring to the table are most likely in it for the money

BTW, you still haven't answered my question, about the fusible switch. How are you going to keep someone from overfusing it after you leave, are going to ride by every day and check it from now to when ever?

We can only do what we can do and if we do it correctly and to the code we can go home and sleep well, at least I do.

Roger

 

[jetlag]

Jetlag, do you have statistics for this comment. I beg to differ. I truly believe there are very few house fires due to wiring. Also I would bet that a 30 amp fuse on a #12 wire would likely, in time, fray the insulation and short out but not cause a wire-- the old knob & tube would probably fair better yet.

I have used a caliper to measure some of the wires in the pre 50 's homes and they are less than #16 conductors on some , I dont know what the stated wire size would have been . These sockets would accept a 30 amp fuse . They didnt have wire nuts then and a lose connection might do ok at less than 15 amp , jump it to thirty and it arcs . I have statistics , I will see what I can find for you , And you know how they put the pennies in , but thats another topic :grin:

 

[Dennis Alwon]

I have used a caliper to measure some of the wires in the pre 50 's homes and they are less than #16 conductors on some , I dont know what the stated wire size would have been . These sockets would accept a 30 amp fuse . They didnt have wire nuts then and a lose connection might do ok at less than 15 amp , jump it to thirty and it arcs . I have statistics , I will see what I can find for you :grin:

I have never seen 16 gauge wire used in a home except as an illegal install. The ground wire in the old romex was 16 gauge but not the conductors for power.

 

[jetlag]

Take a look at the Ilsco site pertaining to distribution blocks and look for an ampacity on the chart, that should be good enough. Terminals are rated according to temperature, according to 110.14(C).

All the terminals on the sheet linked to are 90?.

Well I believe if 400 amps are put on the line in lugs on a 200 amp panel the temperature would exceed the 90 c rating . What do you think the temperature would be ?

 

[George Stolz]

Well I believe if 400 amps are put on the line in lugs on a 200 amp panel the temperature would exceed the 90 c rating . What do you think the temperature would be ?

The calculated load is 194A. The wire's insulation will last to 195A. The terminal will last to 290A. Why are you suddenly more concerned about the terminal than the wire?

 

[jetlag]

The calculated load is 194A. The wire's insulation will last to 195A. The terminal will last to 290A. Why are you suddenly more concerned about the terminal than the wire?

The wire is my concern , I just added the lugs and meter socket as another reason , and I had to reply to the posts after that .

 

[jetlag]

Nope, I don't buy it and you didn't answer my question about the fusible switch.

Roger

And you didnt answer my question about what would any one gain by wiring a box this way as opposed to using the feed thru lugs . With the fed thru the 200amp could not be exceeded .

 

[klineelectric]

So you can install a 200a main breaker panel with feed-through lugs to a 200a main lug panel next to it. Just seems like bad practice having the full load of the second panel flowing through the first. It would be much safer and not that much more $ to just put in the 320meter with double lugs and feed both panels seperatly. jmo

 

[roger]

And you didnt answer my question about what would any one gain by wiring a box this way as opposed to using the feed thru lugs . With the fed thru the 200amp could not be exceeded .

If it were me and I had lugs on the line side that would accomodate my conductors verses making a run to the supply house or back to the shop to get lugs to attach to the busses, I would use what was there and sleep well, it might be as simple as that, now answer mine.

Roger

 

[infinity]

Well I believe if 400 amps are put on the line in lugs on a 200 amp panel the temperature would exceed the 90 c rating . What do you think the temperature would be ?

With 400 amps of load you won't need to worry about the lugs. The #2/0 conductors would probably go first.

But back on topic, the issue here is not whether or not this is a good design, it's whether or not the installation is code compliant. I think that we all agree that we would find a better way to install this service.

 

[roger]

So you can install a 200a main breaker panel with feed-through lugs to a 200a main lug panel next to it.

Yes you can

Just seems like bad practice having the full load of the second panel flowing through the first.

How would this be different than putting 400 amps of face value breakers in a 200 amp panel?

It would be much safer and not that much more $ to just put in the 320meter with double lugs and feed both panels seperatly. jmo

And say we change everything else to 800 amps then.

Roger

 

[klineelectric]

As long as YOU are paying, anything can be done, lol

 

[klineelectric]

Yes you can

How would this be different than putting 400 amps of face value breakers in a 200 amp panel?

And say we change everything else to 800 amps then.

Roger

Not many 800a residential services around here, but 300-400 are almost common place.

 

[jetlag]

So you can install a 200a main breaker panel with feed-through lugs to a 200a main lug panel next to it. Just seems like bad practice having the full load of the second panel flowing through the first. It would be much safer and not that much more $ to just put in the 320meter with double lugs and feed both panels seperatly. jmo

The 320 meter is the way it should be , The fed through lugs are at the end of the buss and would be safe but would only give more breaker spaces because the first 200 amp main will limit the amps to 200 . The debate is going here about installing both panels on the line in lugs of the first panel when the service conductors are only rated 200 amp .I that case the load could reach 400 amp . Believe it or not the code allows it .

 

[roger]

Not many 800a residential services around here, but 300-400 are almost common place.

My point is that the same scenario could exist on a 400 amp service.

Roger