Circuit Breaker teardown and defective Siemens latching mechanism

[mbrooke]

............

 

[mbrooke]

Also to point something else out, your link says 5.5mm2 can not go on a breaker more then 25amps, but PEC actually lets it go on a 30, which is fine. I know not a question, but just felt tempted to point it out.

 

[tersh]

Here is the table from your Code, the Philippine Electrical Code. The thing is, the amapcities are identical to our old table which is good, but the mm2 listed do not reflect the actual size of our wires. They seem to be rounded up or down- for example 2.08 is rounded down to 2.0, 3.31 is rounded up to 3.5mm2, 5.26 is rounded up to 5.5mm2.


My question is, if you have a 12 gauge wire in the Phillipines, is it actually 3.31mm2 or 3.5mm2? What does the jacket say on the wires?

The jacket says 3.5mm^2.

The ampacity used in the Phelph Dodge list is 30A+, but this is for 90C which we can't use because our breakers are only rated at 75C, right? So we must really use

AWG 12 - 20A (60C), 25A (75C), 30A (90C)

25A which is for 75C. So it's 3.5mm^2 for 75C. What do you mean the conductor is small for the listed current. It's actually bigger, isn't it?

Unless you mean 38mm^2 which is based on AWG 1 (42.4mm^2). The ampere table is based on AWG 1.

So at certain threshold (starting 30mm^2 which is rounded off from higher size), the conductor is small for the listed current, this was what you meant?

 

[mbrooke]

The jacket says 3.5mm^2.

I'm surprised they make a specific size for the Philippine market. It would be easier to just take one or two of the already in place global standards.

The ampacity used in the Phelph Dodge list is 30A+, but this is for 90C which we can't use because our breakers are only rated at 75C, right? So we must really use

AWG 12 - 20A (60C), 25A (75C), 30A (90C)

25A which is for 75C. So it's 3.5mm^2 for 75C. What do you mean the conductor is small for the listed current. It's actually bigger, isn't it?

It is, but 2.0mm2 is less then 2.08mm2... but then again looking at it again I don't think it would make that much of an issue. I mean in Europe you have 1.5mm2 used for 16 amp circuits, so in the end I'd say I was to quick to speak. :ashamed1:

Unless you mean 38mm^2 which is based on AWG 1 (42.4mm^2). The ampere table is based on AWG 1.

So at certain threshold (starting 30mm^2 which is rounded off from higher size), the conductor is small for the listed current, this was what you meant?

Yes, but it does not look like a huge difference now that I think about it.

 

[tersh]

I'm surprised they make a specific size for the Philippine market. It would be easier to just take one or two of the already in place global standards.




It is, but 2.0mm2 is less then 2.08mm2... but then again looking at it again I don't think it would make that much of an issue. I mean in Europe you have 1.5mm2 used for 16 amp circuits, so in the end I'd say I was to quick to speak. :ashamed1:





Yes, but it does not look like a huge difference now that I think about it.

I asked a veteran to compute.

He noticed 30mm^2 is exactly between AWG 3 and AWG 2
and 38mm^2 is exactly between AWG 2 and AWG 1

So he figured the ??? is

90, 107, and 122, respectively.
and the *** is

102.5, 122.5 and 137.5 respectively.

For the 38mm^2. Our code used ampere rating of AWG 1 which is 130A instead of 122.5A. Is this what you mean the difference is lesser than it seems? But who the heck created the 30mm^2 and 38mm^2 standard to be exactly halfway between AWG 3, 2, and 1? and used the higher AWG equivalent ampacity.. maybe for economy of wire manufacturing?

Maybe it's because we don't use derating factor in home dwelling for conductor and feeders against the overcurrent protector sizes. But how about in commercial applications where derating doesn't apply?​

​

 

[mbrooke]

I asked a veteran to compute.

He noticed 30mm^2 is exactly between AWG 3 and AWG 2
and 38mm^2 is exactly between AWG 2 and AWG 1

So he figured the ??? is

90, 107, and 122, respectively.
and the *** is

102.5, 122.5 and 137.5 respectively.

For the 38mm^2. Our code used ampere rating of AWG 1 which is 130A instead of 122.5A. Is this what you mean the difference is lesser than it seems?​

​

Yes. It is lesser, but, when compared to the IEC 35mm2 is rated 125amps with 70*C insulation when in conduit not in contact with thermal insulation.

If we assume 90*C insulated wire, then 35mm2 is rated 164 amps in conduit not in contact with thermal insulation.


Clipped direct ratings are yet higher for both.

But who the heck created the 30mm^2 and 38mm^2 standard to be exactly halfway between AWG 3, 2, and 1? and used the higher AWG equivalent ampacity.. maybe for economy of wire manufacturing?

Maybe it's because we don't use derating factor in home dwelling for conductor and feeders against the overcurrent protector sizes. But how about in commercial applications where derating doesn't apply?

No idea why- In truth part of me thinks that your wire isn't actually 38mm2 but 42.41mm2 listed as 38mm2. Its a guess on my part- just seems odd to do it that way especially when you need specific dies when 35mm2 and 42.41mm2 is sitting on every shelf across globe.



In any event- compare with the IEC. Its the absolute max ampacity I would feel comfortable pushing wires to.


​

​

 

[mbrooke]

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[tersh]

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Hmm.. say do you have videos what would happen if your awg 1 wire is put into current of 145A? Would the temperature become 90C? Id like to know when the insulation melts and catch fire? Or test of any wire sizes. Tnx.

 

[mbrooke]

Hmm.. say do you have videos what would happen if your awg 1 wire is put into current of 145A? Would the temperature become 90C? Id like to know when the insulation melts and catch fire? Or test of any wire sizes. Tnx.

Sadly none that I know of

 

[tersh]

Yes. It is lesser, but, when compared to the IEC 35mm2 is rated 125amps with 70*C insulation when in conduit not in contact with thermal insulation.

If we assume 90*C insulated wire, then 35mm2 is rated 164 amps in conduit not in contact with thermal insulation.


Clipped direct ratings are yet higher for both.






No idea why- In truth part of me thinks that your wire isn't actually 38mm2 but 42.41mm2 listed as 38mm2. Its a guess on my part- just seems odd to do it that way especially when you need specific dies when 35mm2 and 42.41mm2 is sitting on every shelf across globe.



In any event- compare with the IEC. Its the absolute max ampacity I would feel comfortable pushing wires to.

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No. It's really 38mm^2. This is because in the AWG 1, the outside diameter of THHN is 12.5mm. see: http://www.panduit.com/heiler/SelectionGuides/WW-WASG03 Electrical Wire Sizes-WEB 7-7-11.pdf

While for the local 38mm^2, it's outside diameter for THHN is 10.8mm, see:

https://phelpsdodge.com.ph/wp-content/uploads/2015/07/COPPER-BUILDING-WIRE-TYPE-THHNTHWN-21.pdf


Last year I let the electrician measured the 38mm^2 in the panel and it measured exactly 10.8mm, see

It should measure 12.5mm if it's really AWG 1 (42.41mm^2) THHN.

Note we are talking of same THHN wire class.

Maybe the reason is savings of cooper wire per reel when the current difference is just 8A (between 122.5A for 38mm^2 and 130A for 42.41mm^2, both for 75C?

Can you compute the savings in cooper wire per reel?

 

[kwired]

Hmm.. say do you have videos what would happen if your awg 1 wire is put into current of 145A? Would the temperature become 90C? Id like to know when the insulation melts and catch fire? Or test of any wire sizes. Tnx.

I'm not going to claim to know exactly how to determine what that melting point will be or for that matter what temp conductor with load you mentioned will operate at.

What I do know - 90C conductor shouldn't have major deterioration effect at 90C operating temp.

Said conductor still is usually landed on a 75C rated terminal - termination failure often occurs before insulation failure away from terminations ever fail.

Most insulation failure I have seen doesn't ever melt to the point it drips or runs, but eventually it gets really brittle and breaks apart if you happen to flex the conductor.

Also keep in mind most common used NEC ampacity table is 310.15(B)(16) it is based on ambient temp of 30C. Lower the actual temp and you can have more current before insulation reaches a compromising temperature point.

Tables we have are somewhat conservative on the "safe side" for good reason. They are not precision calculations, just a general calculation with some safety factor built into them. Not very often does a 90C conductor actually operate at 90C.

 

[mbrooke]

No. It's really 38mm^2. This is because in the AWG 1, the outside diameter of THHN is 12.5mm. see: http://www.panduit.com/heiler/SelectionGuides/WW-WASG03 Electrical Wire Sizes-WEB 7-7-11.pdf

While for the local 38mm^2, it's outside diameter for THHN is 10.8mm, see:

https://phelpsdodge.com.ph/wp-content/uploads/2015/07/COPPER-BUILDING-WIRE-TYPE-THHNTHWN-21.pdf


Last year I let the electrician measured the 38mm^2 in the panel and it measured exactly 10.8mm, see

It should measure 12.5mm if it's really AWG 1 (42.41mm^2) THHN.

Note we are talking of same THHN wire class.

Maybe the reason is savings of cooper wire per reel when the current difference is just 8A (between 122.5A for 38mm^2 and 130A for 42.41mm^2, both for 75C?

Can you compute the savings in cooper wire per reel?

Maybe it is indeed that size.


BTW, its possible those values are not just rounded, but actually adjusted to fit the listed ampacity now that I think about it.


For example, 2.08mm2 is actually good for 18amps; 3.31mm2 gets hotter then 2.08mm2 for the same % overload.


In fact I'd argue that if you took all the wire sizes, put them in the same controlled environment and loaded them to their rated 60, 75 and 90*C ratings some would be hotter some cooler.


Keep in mind that the AWG system for wire is more then 100 years old, and I doubt they were as well thought out as if we were to do it today. Many of the amapacity values in 310.15 B 16 are rounded up or down from the "actual" values.


It would be nice if someone made a system where wire size was based directly off the common amapacities seen in the industry, ie 15, 20, 30, 40, 50, 60, 80, 100, 125, 150, 200 ect.

Honestly, you have peaked my curiosity! :happyyes::happyyes:

 

[tersh]

Maybe it is indeed that size.


BTW, its possible those values are not just rounded, but actually adjusted to fit the listed ampacity now that I think about it.


For example, 2.08mm2 is actually good for 18amps; 3.31mm2 gets hotter then 2.08mm2 for the same % overload.


In fact I'd argue that if you took all the wire sizes, put them in the same controlled environment and loaded them to their rated 60, 75 and 90*C ratings some would be hotter some cooler.


Keep in mind that the AWG system for wire is more then 100 years old, and I doubt they were as well thought out as if we were to do it today. Many of the amapacity values in 310.15 B 16 are rounded up or down from the "actual" values.


It would be nice if someone made a system where wire size was based directly off the common amapacities seen in the industry, ie 15, 20, 30, 40, 50, 60, 80, 100, 125, 150, 200 ect.

Honestly, you have peaked my curiosity! :happyyes::happyyes:

Maybe we have some wire experts who can chime in.

Meanwhile I have a question for you.

Yesterday I received the Siemens Load Panel Lugs. Shown in the middle.

The battery is just comparison of the sizes of them. The one on the right is a generic chair lugs.

My 2 questions:

1. Notice the pointed screw of the middle compare to the flat screw on the right. What is your experiences about them? Are there certain wire sizes limit before each can be used? I'm imagining that if you put a smaller AWG 10 in the larger pointed screw lugs, it can slip compared to the flat screw on the right? So are there sizes optimum for the pointed and flat screw?

2. Second. I ordered the middle just to see how flat is the metal contacts. But when two of the middle are put flat on each other. You can still see spacing between the flat contact points. Do you know what brand is Milspec flat? Because if it is not so flat. There may not be full contact between it and bus bar and not optimum electrical conduction. I know it is sufficient but just want to own some Milspec lugs that are dead flat. No. It's not to be used on the Siemens load panel but just to own a sample. Thanks.

 

[jmellc]

Sounds like a defective unit.

We have discover that many CH 200 amp main breakers will not either turn off the power or the handle will just flip back up without engaging the mechanism. We installs many of these in the 90's and now I have gone back to about 5 different jobs where we had to work on the service and discovered they were defective. CH started to cover the cost of the breaker but now has refused to do so. I think they have had a defective batch that never got caught because no one usually turns the main on and off again on install.

CH tan handle? I hadn't heard of this before.

 

[mbrooke]

Maybe we have some wire experts who can chime in.

Meanwhile I have a question for you.

Yesterday I received the Siemens Load Panel Lugs. Shown in the middle.

The battery is just comparison of the sizes of them. The one on the right is a generic chair lugs.

My 2 questions:

1. Notice the pointed screw of the middle compare to the flat screw on the right. What is your experiences about them? Are there certain wire sizes limit before each can be used? I'm imagining that if you put a smaller AWG 10 in the larger pointed screw lugs, it can slip compared to the flat screw on the right? So are there sizes optimum for the pointed and flat screw?

2. Second. I ordered the middle just to see how flat is the metal contacts. But when two of the middle are put flat on each other. You can still see spacing between the flat contact points. Do you know what brand is Milspec flat? Because if it is not so flat. There may not be full contact between it and bus bar and not optimum electrical conduction. I know it is sufficient but just want to own some Milspec lugs that are dead flat. No. It's not to be used on the Siemens load panel but just to own a sample. Thanks.

What does the package say?

 

[tersh]

What does the package say?

It say 4 - 300kcmil... so it's from AWG 4 to 300kcmil. So it's not for AWG 10. Ok.

But note 300kcmil is rated at 285A

https://www.usawire-cable.com/pdfs/NEC AMPACITIES.pdf

While the product is listed only for 100A to 125A in the Siemens panel.

https://www.alliedelec.com/product/siemens/ecmlk125/70820884/

Maybe it's OEM and not really manufactured by Siemens itself? And Siemens just got it from OEM and prefer larger to make it nice on the bus bar basepan?

But my real concern is this. In our locally distributed chair lugs (see following pic at right side, just good for AWG 1, and not something so big for up to 300kcmil (the siemens panel lugs is at left side).. which can affect placement if so big). It doesn't have any markings, UL, etc. It doesn't even indicate what size wire allowed, and it's made in china distributed by a supplier and mostly used in service entrance bus bar and gutter around the country. The contacts are not so flat.

I'm just looking for a US made quality chair lugs with UL marking that can accept up to AWG 1. Any ideas what it may be?

 

[mbrooke]

It say 4 - 300kcmil... so it's from AWG 4 to 300kcmil. So it's not for AWG 10. Ok.

But note 300kcmil is rated at 285A

https://www.usawire-cable.com/pdfs/NEC AMPACITIES.pdf

While the product is listed only for 100A to 125A in the Siemens panel.

https://www.alliedelec.com/product/siemens/ecmlk125/70820884/

Maybe it's OEM and not really manufactured by Siemens itself? And Siemens just got it from OEM and prefer larger to make it nice on the bus bar basepan?

Are you sure those lugs are meant for a 125 amp load center? They look more like for a 200amp load center. Maybe they aren't- I haven't payed attention to many Siemens panels.


Sometimes conductors are up-sized for voltage drop.


The rating of the panel is determined by the busbar itself- 125 amps and 225amps are to common ratings.

But my real concern is this. In our locally distributed chair lugs (see following pic at right side, just good for AWG 1, and not something so big for up to 300kcmil (the siemens panel lugs is at left side).. which can affect placement if so big). It doesn't have any markings, UL, etc. It doesn't even indicate what size wire allowed, and it's made in china distributed by a supplier and mostly used in service entrance bus bar and gutter around the country. The contacts are not so flat.

I'm just looking for a US made quality chair lugs with UL marking that can accept up to AWG 1. Any ideas what it may be?

What are you using them for? If you already have a panel, you can give me the model number and I can hunt down the specs.

 

[tersh]

Are you sure those lugs are meant for a 125 amp load center? They look more like for a 200amp load center. Maybe they aren't- I haven't payed attention to many Siemens panels.


Sometimes conductors are up-sized for voltage drop.


The rating of the panel is determined by the busbar itself- 125 amps and 225amps are to common ratings.






What are you using them for? If you already have a panel, you can give me the model number and I can hunt down the specs.

This is the model https://www.amazon.com/P1224B1100CU...&keywords=siemens+pl+load+center+p1224b1100cu

It has included breaker, the listed Lugs is the one I bought and shown, the ECMLK125 https://www.alliedelec.com/product/siemens/ecmlk125/70820884/

I was just asking if you know any quality lugs that is of smaller size (can fit AWG 1), because the only stocks we have in the country are bad quality made in china without any UL marking or no brand listed. It will be shared with other engineers or electricians for use in their installations. I just want an American made lugs (smaller size for AWG 1). Do you know what brand is milspec flat? It's not related to the Siemens panel or Lugs. I just ordered the Siemens Lugs to just see how it looks like (I won't be using it).

 

[mbrooke]

This is the model https://www.amazon.com/P1224B1100CU...&keywords=siemens+pl+load+center+p1224b1100cu

It has included breaker, the listed Lugs is the one I bought and shown, the ECMLK125 https://www.alliedelec.com/product/siemens/ecmlk125/70820884/

I was just asking if you know any quality lugs that is of smaller size (can fit AWG 1), because the only stocks we have in the country are bad quality made in china without any UL marking or no brand listed. It will be shared with other engineers or electricians for use in their installations. I just want an American made lugs (smaller size for AWG 1). Do you know what brand is milspec flat? It's not related to the Siemens panel or Lugs. I just ordered the Siemens Lugs to just see how it looks like (I won't be using it).

1 AWG will work.


Hoping other members chime in...

 

[tersh]

1 AWG will work.


Hoping other members chime in...

I know 1 AWG will work with the Siemens Lugs. But it has a bottom with strip (shown at left)). I need something flat like in the right one (but the right one is china made without any brand, not UL listed and the bottom is not so flat). I just need a branded chair lugs that can accept 1 AWG with flat bottom. Any idea? What brands do you or other electricians/engineers use when such quality chair lugs are required?