Leviton Thermal Magnetic vs Hydraulic Magnetic Circuit Breakers

[mswlogo]

I’m having my electrician install Leviton's new Load Center.

I noticed there are Thermal Magnetic vs Hydraulic Magnetic Circuit Breakers.

I understand the difference See - Leviton Doc on Breakers

The ambient Temp will be 60F possibly as low as 45F (cellar of an extremely well insulated home in the northeast).

He is installing all Thermal Magnetic breakers.

Why would anyone choose Thermal Magnetic over Hydraulic Magnetic, since the Hydraulic Magnetic are stable for all applications and the cost appears to be similar?

Electrician had no idea there was even a choice and said he just takes what the Electrical Supply guy hands him and has no clue.

What's your thoughts.

 

[Canton]

#1 This is a residential installation, I don’t think many electricians get to deep in the weeds over OCPD selection on a residential distribution.
#2 If that’s the Breaker you want, tell him and have it in your contract

 

[mswlogo]

Well, I didn't want to ask if it's a stupid request and wanted something to back it up.

I think even in this "residential" home the breakers trip point will all be 30% higher than they should be. That seems like a lot.
If I'm reading the chart right, even at 68F degrees, they will trip 25% over !!

The Panel is probably typically a little warmer than ambient. They are at spec at 105F.

Like I said, why would anyone ever want the Thermal ones, since they so drastically shift. Even in residential applications can vary from Attic, Garage, Cellar, to living space and drastically change the trip point.

Trying to understand.

 

[ptonsparky]

I don't think you have much to worry about:

SUMMARY Hydraulic magnetic circuit breakers are best used in harsh environments where temperatures can vary widely.

15 degrees is not wide and it would take a long time for your basement to change that much.

The difference in cost may not be much, but how about availability?

 

[__dan]

SQD QO breakers have always been thermal magnetic and have the best tripping action of any breaker in that range. GE I believe were hyd magnetic and would trip impressively sometimes but seemed slower, more let through when it needs to trip (just by eye and experience).

Everyone else I consider dog brands in that range.

I would say brand would have more impact on quality that thermal or hyd delaying action in that size range, ie, I would say you're looking at the wrong thing. Never seen Leviton's panel breaker system. But where you buy makes a difference. If he bought it at big Orange, they have no clue what they sell and it could very well be wrong. The supply house otoh, does know their business and does not want to sell something they will have trouble with, customer grief.

So, instead of depending on the trip curves for residential breakers (most guys would just plug in a table saw and see what it does), you're depending on the personal business expertise of the contractor / supply house relationship. Either they went with the cheapest thing they could find, or they went with something they personally like even if it costs more because they feel they're getting best value and trying to pass that on to the customer.

And yes, the breaker will usually hold at 125% for some time delay but not forever hopefully.

 

[hbiss]

You must be an engineer, you overthink.

I would never install a Leviton load center, plastic, wouldn't go near it. They recently added load centers to their otherwise good product line. Other manufacturers like Square D have been around for 75 years. I have no idea why they offer the choice of hydraulic or magnetic trip. That's unheard of anywhere else for residential. Probably a gimmick.

I would stick with established panels from other manufacturers who know how to make them.

-Hal

 

[__dan]

I would add that in my experience and opinion, in that size range of equipment, the thermal trip is much better calibrated to the nameplate handle trip rating, ie, if it says 20, it knows 22 is a running overload. Mag only breakers (Bryant comes to mind) would trip the main when the AC starts.

Magnetic trips I don't believe they have an accurate calibration in any size range, except for the instantaneous trip at 10 times the handle number. That they do very well.

Before the modern electronic trip units which are very good, all larger breakers were all thermal magnetic. Thermal for the better calibration at near running overloads and magnetic for the fast instantaneous trip.

Which is why in residential sized breakers, mag only were always a joke to me. Common to show up on a job and the guys are running a table saw, skill saw, and a large drill all on one extension cord. The breakers would buzz but not trip.

I would be more concerned with getting a tin plated copper bus and as Hal says, a steel enclosure.

 

[mswlogo]

I don't think you have much to worry about:

SUMMARY Hydraulic magnetic circuit breakers are best used in harsh environments where temperatures can vary widely.

15 degrees is not wide and it would take a long time for your basement to change that much.

The difference in cost may not be much, but how about availability?

The difference between 105F that they are spec'd for and my cellar which will easily be below 60F is a lot and can make a 25% shift in trip point. A 20A breaker will trip at 25A. And my 50A breaker will trip at 62.5A that seems like an awful lot.

I don't think it would be a big deal if it wasn't for such a steep slope.

I ordered a couple Hydraulic magnetic breakers myself and had no issue getting them. Same price too.

I'm sure residential applications vary much more than 15F. Like a Sub Panel in unheated garage which goes below 0F to say an finished Attic space with no AC that could reach 100F, easy. That equates to 50% swing in trip point. Some residential panels are in unheated spaces.

I'm confused by your comment though and maybe that's where I'm confused. No, my basement won't change that much. It will probably be 55F in Winter and 75F in summer. But it's the 55F relative to 105F (that they meet spec at) is most concerning.

Are you implying it's some sort of relative temperature change?

 

[mswlogo]

You must be an engineer, you overthink.

I would never install a Leviton load center, plastic, wouldn't go near it. They recently added load centers to their otherwise good product line. Other manufacturers like Square D have been around for 75 years. I have no idea why they offer the choice of hydraulic or magnetic trip. That's unheard of anywhere else for residential. Probably a gimmick.

I would stick with established panels from other manufacturers who know how to make them.

-Hal

Plastic? There is no more plastic than any other panel I've seen.

Electrician did comment that he absolutely loves working with the panel.

I wanted the smart breakers to monitor GeoThermal, EV and a few other big items. I plan to put the hub in this week. Admittedly Smart breakers are excessively expensive though. The other breakers are are all typically prices.

Gimmick? I doubt it.

 

[mswlogo]

I would add that in my experience and opinion, in that size range of equipment, the thermal trip is much better calibrated to the nameplate handle trip rating, ie, if it says 20, it knows 22 is a running overload. Mag only breakers (Bryant comes to mind) would trip the main when the AC starts.

Magnetic trips I don't believe they have an accurate calibration in any size range, except for the instantaneous trip at 10 times the handle number. That they do very well.

Before the modern electronic trip units which are very good, all larger breakers were all thermal magnetic. Thermal for the better calibration at near running overloads and magnetic for the fast instantaneous trip.

Which is why in residential sized breakers, mag only were always a joke to me. Common to show up on a job and the guys are running a table saw, skill saw, and a large drill all on one extension cord. The breakers would buzz but not trip.

I would be more concerned with getting a tin plated copper bus and as Hal says, a steel enclosure.

Thanks for the info.

The buss is copper and the enclosure is steel. I think people see the white and think it's plastic.

 

[ptonsparky]

Plastic? There is no more plastic than any other panel I've seen.

Electrician did comment that he absolutely loves working with the panel.

I wanted the smart breakers to monitor GeoThermal, EV and a few other big items.

Gimmick? I doubt it.

I haven't installed any, but I thought the enclosure was all nonmetallic. That's nice.

Widely varying to me would be 50 degrees in a few hours. Not a month or two.

 

[mswlogo]

Widely varying to me would be 50 degrees in a few hours. Not a month or two.

I agree, but that's not the point, I don't think.

Do the thermal breakers recalibrate themselves (on temperature)?

Let's put it this way, if the cellar is at 50F for 3 months, will a Thermal Magnetic 20A breaker trip around 21 amps or 25 amps?

 

[Canton]

I agree, but that's not the point, I don't think.

Do the thermal breakers recalibrate themselves (on temperature)?

Let's put it this way, if the cellar is at 50F for 3 months, will a Thermal Magnetic 20A breaker trip around 21 amps or 25 amps?

Dude, what everyone is trying to tell you is you are really overthinking this one. Have the electrician put the hydraulic breakers in so you sleep better.

 

[__dan]

Nice looking panel but if that's a load side tab and the load wire goes to a bus terminal, I would not like that. The bus stabs are a common failure point and having two of them is not an improvement. Very nice looking otherwise.

The breaker is not calibrated to trip accurately at 105 F. Your basic premise is wrong. Also you're citing a non existing ambient for your application of the attic location in hot summer then the outside wall garage location in January. To be fair to your electrician, this is not something to bother him with timewise or otherwise.

But it is now time to test the actual against the table values, meaning a load test. Get two hairdryers and plug them it, get the running current and time to trip, then repeat with the hydraulic breaker to see if you do in fact have a preference (I am guessing the electrician did not include this in his bid).

My guess is that the thermal trip will be better for calibration at near running overloads but the hydraulic delayed mag trip could be a preference for select loads, possibly for motors but idk. It's actually a question for the Leviton applications rep when you should go to mag trip over thermal, not the supply house or the EC. I would guess hyd delayed mag trip would give less nuisance trips for hard starting motors but that's just a guess. Leviton knows why they make both, and it's not for the consumer to choose.

Load test it and see what it does. That information is not in the table trip curves, not at that accuracy.

 

[norcal]

Leviton panels bring one word to mind with me, Trilliant, are they going to be like SQ D Trilliant & become extinct making breakers scarce & expensive?

 

[suemarkp]

Do you have any Arc Fault breakers in that panel (a residential panel should have a lot of them if under 2020 code)? Those make some heat. My subpanel with 20 of them is rather warm (rarely under 100F) unless it is quite cold in the garage.

 

[mswlogo]

Dude, what everyone is trying to tell you is you are really overthinking this one. Have the electrician put the hydraulic breakers in so you sleep better.

Well, according to @__dan 's informative post that would be a really bad idea.

 

[hbiss]

Plastic? There is no more plastic than any other panel I've seen.

I apologize. Seeing your picture, Leviton must have changed to conventional steel cabinets from plastic due to lack of sales.

-Hal

 

[mswlogo]

I apologize. Seeing your picture, Leviton must have changed to conventional steel cabinets from plastic due to lack of sales.

-Hal

How about backing that up? Because I don't think they were ever plastic cabinets.

Do you have any Arc Fault breakers in that panel (a residential panel should have a lot of them if under 2020 code)? Those make some heat. My subpanel with 20 of them is rather warm (rarely under 100F) unless it is quite cold in the garage.

Honestly, I'm afraid to ask about the Arc Faults. In some ways I prefer he just install the cheapest breakers and move on so I can put in what I want. I don't know how much I want to invest in the smart breakers (which only come in Hydraulic BTW). I bought a couple smart breakers and the hub to try out this week.

So far he only put in 4 temp circuits, Well Pump (DC variable speed), GeoThermal (variable speed compressor)/ GeoThermal backup

I have almost all AFCI, GFCI or Combo's in my current panel and it doesn't run warm at all. It's a Murray panel. The AFCI actually found a faulty light fixture. Love them. No false trips at all either.

 

[mswlogo]

The breaker is not calibrated to trip accurately at 105 F. Your basic premise is wrong. Also you're citing a non existing ambient for your application of the attic location in hot summer then the outside wall garage location in January. To be fair to your electrician, this is not something to bother him with timewise or otherwise.

Actually they are pitching these Hydraulic breakers for better accuracy in residential temperature applications (see Video). No, I'm not putting it in my garage. But if the house is well insulated, the cellar will be as cold as some garages (they even use a garage as an example in the Video). I was just giving examples of residential applications that vary widely in temperature. Because the Thermal breakers are designed to trip at spec at a specific Ambient temperature with a steep re-rating temperature curve. Residential applications can range from 0F-100F easy. And that can shift the trip point a lot.

No, I don't plan on load testing them jump to 1:41