1st. encounter with Pushmatic Breakers

[partimer31]

Pushmatiic circuit breaker panel. Very old, with rust stains.

Panel does not have a split bus design.

I call the left vertical power bus, Phase A.

I call the right vertical power bus, Phase B.

Bolted to Phase A, is a single pushmatic 30 A. circuit breaker

Bolted to Phase B, is a single pushmatic 20 A. circuit breaker

Together, They make one single 240 volt circut.

240 volt load is a electric storage hot water tank. This tank has both
an upper and lower heating elements. I check then both. And they
tested okay at the time, the upper would come up temperature, then the
control would switch over one leg of the 240 volt circuit down to the
lower element thermostat control, which passes the 120 volt to the lower
element. The other leg of this 240 volt circuit, Phase B, is parallel
wired to both upper and lower element.

The other leg of this 240 volt circuit is connected to both upper and
lower elements, (phase B), by being wired in parallel. (there are not
controls or thermostat wire into this circuit)

The electric hot water tank works most of the time, but lately the 30 A.
breaker has been tripping, it least once a day,

I am puzzle, why the 30 A. breaker and not the 20 A. breaker.

I thinking about replacing all upper and lower thermostats, plus the upper
control on the hot water. Or should I just buy a new P230 pushmatic
30 A. breaker, this would eliminate the two individual breakers, making up
the 240 volt circuit to the electric hot water tank.

Any suggestion, other them complete replacement of the pushmatic circuit
breaker electrical panel.

 

[ptonsparky]

You probably have an element out as you have figured out. The fault is probably closer to the 30A breaker thus passing more current thru it. Have you checked the element for resistance to ground? Usually just a good ohm meter will work for this.

A new breaker is the best way to go but you may have to search around for one.

 

[SEO]

As ptonsparky stated check your elements. Disconnect wires on elements and take readings . You should have an open reading from each terminal to ground. If you have an open reading to ground read between the terminals on the element and do the calculations using ohms law to check the element. A 4500 w element at 240v is aprox 12.8 ohms a 3000 is aprox 19.2 ohm. Also install the proper sized two pole breaker. Could be as simple as a tired circuit breaker.

 

[benaround]

PTer, Before you go replacing all those parts, find out what the problem is ! The 2-pole

circuit breaker is a must do. IMO, 9 out of 10 times it's an element that needs replacing.

 

[cadpoint]

...
240 volt load is a electric storage hot water tank. This tank has both
an upper and lower heating elements. I check then both. And they
tested okay at the time, the upper would come up temperature, then the
control would switch over one leg of the 240 volt circuit down to the
lower element thermostat control, which passes the 120 volt to the lower
element. The other leg of this 240 volt circuit, Phase B, is parallel
wired to both upper and lower element. I think someones been in there ...

Wow, switch a leg and between different circuit breakers, Is that what I'm reading ? :roll: I'm must wondering if that power is still being draw from that first one element left ... I think someones been in there, I thought the control of the water heater was for the exact conrtol of both elements, sounds like they wanted alot of hot H20, fast... maybe this draw has finally tired that breaker(as said)...

Can you still read the road map on the water heater? I'm sure (well almost) you could find a (near like) diagram to use from the i-net.

 

[cadpoint]

I wonder if the older breakers are more suspect to being activied by temperature, verses today's?
Spring loaded, Push-matic... :grin:

Good Luck!

 

[iwire]

Typical electric water heater wiring.

 

[partimer31]

Pushmatic breakers and the electric water tank

Pushmatic breakers and the electric water tank

Thank guys for all your answers.

But do you think with this electrical panel, replacement is the best way
to go? If the owner would agree to go that route.

 

[ptonsparky]

Just depends on the money your customer has. We try to install new when we can but just for one CB is stretching it.

 

[LarryFine]

The electric hot water tank works most of the time, but lately the 30 A.
breaker has been tripping, it least once a day,

I am puzzle, why the 30 A. breaker and not the 20 A. breaker.

I wouldn't replace anything until you determine whether the breaker is tripping because it should, or because it's bad. I'd use a clamp ammeter to see what the current is when it trips.

Because the higher-rated breaker is the one tripping, I'd also be sure to test the current in both circuit conductors, just in case you're correct that there is a fault on the 30a phase.

 

[LarryFine]

Wow, switch a leg and between different circuit breakers, Is that what I'm reading ? :roll:

Not at all. That's how water heaters are wired. There's no requirement to switch both line conductors for control, only for disconnecting.

 

[partimer31]

What little I know about pushmatic circuit breakers.

What little I know about pushmatic circuit breakers.

LarryFine; many thanks for the advice. Will do.


Iwire; your posting the hot water tank wiring diagaram, has help me
better understand the workings of the electric hot water tank.

Now that I have a road map. (humor)