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| Author |
Switching off ONLY one pole on a 220V pump
|
|
| letterman@invalid.com 2008-01-31, 9:25 am |
|
I have a 220V submercible well pump. I am not going to even try to
describe the location of the control box, pressure switch, etc. It's
an odd situation because the pressure tank is in an underground
concrete pit and the control box is in my garage, with the well
outside in another location.
Anyhow, because the wires were embedded into the conrete of the pit,
and only used a 2 wire UF cable, I can only switch one side of the
220. Otherwise I'd have to do some major digging and concrete removal
underground. The control box is wired correctly to the pump. It's
just that the pressure switch only switches one side (pole) of the
220.
This has been this way for years, and works fine. However, I just had
my tank rupture and although I worked as a plumber for years before I
retired, I could not get into this pit with the cover frozen shut. I
finally called a plumber, who had to contact another guy to remove the
frozen soil. When we opened the pit, it was nearly filled with water,
and the electrical connections were under water. That lead to him
bringing a pump to pump the pit dry.
Anyhow, the weather has been so severe that I just let him finish the
job, after buying the tank and a new pressure switch myself. (I just
dont function well in severe cold anymore). He did a good job, the
cost was not as bad as I thought it might be, and I have water again.
However, the plumber told me that I should really be switching off
BOTH poles of the 220 on the pressure switch. I honestly can not see
why. On a light switch you only shut off one of the two wires......
Why should it matter whether it's 110 or 220? It's still the same
circuit.
One thought I do have to solve this is to apply a low voltage to those
two wires, and use the low voltage to flip a heavy duty double pole
relay inside the garage. That would switch both poles of the 220, yet
not require any digging. Another advantage, if the pit filled with
water again, I would not have live 220 voltage under water. (It still
amazes me the breaker never blew, the pump just would not run while
those wires were submerged).
I guess this would be the solution and would not be that hard to wire,
but is it really necessary?
Thanks
| |
|
| For safety, you want a disconnect to kill both legs of the feed. For the
operation of the pump, using both poles of the pressure switch pulls less
current per pole, so the switch will last longer. Depending upon the HP of
the pump and switch, this may not be that important. You can also install
jumpers in the pressure switch so the two poles work together to close the
one circuit.
<letterman@invalid.com> wrote in message news:fnscj7$atn$1@aioe.org...
>
> I have a 220V submercible well pump. I am not going to even try to
> describe the location of the control box, pressure switch, etc. It's
> an odd situation because the pressure tank is in an underground
> concrete pit and the control box is in my garage, with the well
> outside in another location.
>
> Anyhow, because the wires were embedded into the conrete of the pit,
> and only used a 2 wire UF cable, I can only switch one side of the
> 220. Otherwise I'd have to do some major digging and concrete removal
> underground. The control box is wired correctly to the pump. It's
> just that the pressure switch only switches one side (pole) of the
> 220.
>
> This has been this way for years, and works fine. However, I just had
> my tank rupture and although I worked as a plumber for years before I
> retired, I could not get into this pit with the cover frozen shut. I
> finally called a plumber, who had to contact another guy to remove the
> frozen soil. When we opened the pit, it was nearly filled with water,
> and the electrical connections were under water. That lead to him
> bringing a pump to pump the pit dry.
>
> Anyhow, the weather has been so severe that I just let him finish the
> job, after buying the tank and a new pressure switch myself. (I just
> dont function well in severe cold anymore). He did a good job, the
> cost was not as bad as I thought it might be, and I have water again.
>
> However, the plumber told me that I should really be switching off
> BOTH poles of the 220 on the pressure switch. I honestly can not see
> why. On a light switch you only shut off one of the two wires......
> Why should it matter whether it's 110 or 220? It's still the same
> circuit.
>
> One thought I do have to solve this is to apply a low voltage to those
> two wires, and use the low voltage to flip a heavy duty double pole
> relay inside the garage. That would switch both poles of the 220, yet
> not require any digging. Another advantage, if the pit filled with
> water again, I would not have live 220 voltage under water. (It still
> amazes me the breaker never blew, the pump just would not run while
> those wires were submerged).
>
> I guess this would be the solution and would not be that hard to wire,
> but is it really necessary?
>
> Thanks
| |
| Joseph Meehan 2008-01-31, 9:25 am |
| With 120 Volt you switch the hot side and the circuit is dead, on 240V
if you switch one side all you end up with a circuit still carrying 120V to
ground. It is a safety issue.
<letterman@invalid.com> wrote in message news:fnscj7$atn$1@aioe.org...
>
> I have a 220V submercible well pump. I am not going to even try to
> describe the location of the control box, pressure switch, etc. It's
> an odd situation because the pressure tank is in an underground
> concrete pit and the control box is in my garage, with the well
> outside in another location.
>
> Anyhow, because the wires were embedded into the conrete of the pit,
> and only used a 2 wire UF cable, I can only switch one side of the
> 220. Otherwise I'd have to do some major digging and concrete removal
> underground. The control box is wired correctly to the pump. It's
> just that the pressure switch only switches one side (pole) of the
> 220.
>
> This has been this way for years, and works fine. However, I just had
> my tank rupture and although I worked as a plumber for years before I
> retired, I could not get into this pit with the cover frozen shut. I
> finally called a plumber, who had to contact another guy to remove the
> frozen soil. When we opened the pit, it was nearly filled with water,
> and the electrical connections were under water. That lead to him
> bringing a pump to pump the pit dry.
>
> Anyhow, the weather has been so severe that I just let him finish the
> job, after buying the tank and a new pressure switch myself. (I just
> dont function well in severe cold anymore). He did a good job, the
> cost was not as bad as I thought it might be, and I have water again.
>
> However, the plumber told me that I should really be switching off
> BOTH poles of the 220 on the pressure switch. I honestly can not see
> why. On a light switch you only shut off one of the two wires......
> Why should it matter whether it's 110 or 220? It's still the same
> circuit.
>
> One thought I do have to solve this is to apply a low voltage to those
> two wires, and use the low voltage to flip a heavy duty double pole
> relay inside the garage. That would switch both poles of the 220, yet
> not require any digging. Another advantage, if the pit filled with
> water again, I would not have live 220 voltage under water. (It still
> amazes me the breaker never blew, the pump just would not run while
> those wires were submerged).
>
> I guess this would be the solution and would not be that hard to wire,
> but is it really necessary?
>
> Thanks
--
Joseph Meehan
Dia 's Muire duit
| |
| David L. Martel 2008-01-31, 9:25 am |
| Letterman,
In a 120v circuit you have a hot wire and a return/ground (or a seperate
ground) in a 220v circuit you have 2 hot wires (each 120v though different
in phase), and a return/ground. Switching off the one pole leaves the other
pole of 120v still actively doing whatever it's doing. In other words there
is always electricity there, a safety hazard.
Your description of this circuit seems odd. Since you worked in the
trades try to get an electrician to look at it and explain to you what's
going on here.
Dave M.
| |
| Blattus Slafaly £ ¥ 0/00 :) 2008-01-31, 9:25 am |
| letterman@invalid.com wrote:
> I have a 220V submercible well pump. I am not going to even try to
> describe the location of the control box, pressure switch, etc. It's
> an odd situation because the pressure tank is in an underground
> concrete pit and the control box is in my garage, with the well
> outside in another location.
>
> Anyhow, because the wires were embedded into the conrete of the pit,
> and only used a 2 wire UF cable, I can only switch one side of the
> 220. Otherwise I'd have to do some major digging and concrete removal
> underground. The control box is wired correctly to the pump. It's
> just that the pressure switch only switches one side (pole) of the
> 220.
>
> This has been this way for years, and works fine. However, I just had
> my tank rupture and although I worked as a plumber for years before I
> retired, I could not get into this pit with the cover frozen shut. I
> finally called a plumber, who had to contact another guy to remove the
> frozen soil. When we opened the pit, it was nearly filled with water,
> and the electrical connections were under water. That lead to him
> bringing a pump to pump the pit dry.
>
> Anyhow, the weather has been so severe that I just let him finish the
> job, after buying the tank and a new pressure switch myself. (I just
> dont function well in severe cold anymore). He did a good job, the
> cost was not as bad as I thought it might be, and I have water again.
>
> However, the plumber told me that I should really be switching off
> BOTH poles of the 220 on the pressure switch. I honestly can not see
> why. On a light switch you only shut off one of the two wires......
> Why should it matter whether it's 110 or 220? It's still the same
> circuit.
>
> One thought I do have to solve this is to apply a low voltage to those
> two wires, and use the low voltage to flip a heavy duty double pole
> relay inside the garage. That would switch both poles of the 220, yet
> not require any digging. Another advantage, if the pit filled with
> water again, I would not have live 220 voltage under water. (It still
> amazes me the breaker never blew, the pump just would not run while
> those wires were submerged).
>
> I guess this would be the solution and would not be that hard to wire,
> but is it really necessary?
>
> Thanks
Why don't you put a sump pump in the 'pit'?
--
Blattus Slafaly ? 3  7/8
| |
| Howard 2008-01-31, 1:25 pm |
| On Jan 31, 6:48 am, letter...@invalid.com wrote:
> I have a 220V submercible well pump. I am not going to even try to
> describe the location of the control box, pressure switch, etc. It's
> an odd situation because the pressure tank is in an underground
> concrete pit and the control box is in my garage, with the well
> outside in another location.
>
> Anyhow, because the wires were embedded into the conrete of the pit,
> and only used a 2 wire UF cable, I can only switch one side of the
> 220. Otherwise I'd have to do some major digging and concrete removal
> underground. The control box is wired correctly to the pump. It's
> just that the pressure switch only switches one side (pole) of the
> 220.
>
> This has been this way for years, and works fine. However, I just had
> my tank rupture and although I worked as a plumber for years before I
> retired, I could not get into this pit with the cover frozen shut. I
> finally called a plumber, who had to contact another guy to remove the
> frozen soil. When we opened the pit, it was nearly filled with water,
> and the electrical connections were under water. That lead to him
> bringing a pump to pump the pit dry.
>
> Anyhow, the weather has been so severe that I just let him finish the
> job, after buying the tank and a new pressure switch myself. (I just
> dont function well in severe cold anymore). He did a good job, the
> cost was not as bad as I thought it might be, and I have water again.
>
> However, the plumber told me that I should really be switching off
> BOTH poles of the 220 on the pressure switch. I honestly can not see
> why. On a light switch you only shut off one of the two wires......
> Why should it matter whether it's 110 or 220? It's still the same
> circuit.
>
> One thought I do have to solve this is to apply a low voltage to those
> two wires, and use the low voltage to flip a heavy duty double pole
> relay inside the garage. That would switch both poles of the 220, yet
> not require any digging. Another advantage, if the pit filled with
> water again, I would not have live 220 voltage under water. (It still
> amazes me the breaker never blew, the pump just would not run while
> those wires were submerged).
>
> I guess this would be the solution and would not be that hard to wire,
> but is it really necessary?
>
> Thanks
Another alternative would be to move the pressure switch to the water
line closest to the control box in the garage. Other than a minor
change in head the pressure switch will work. By moving the switch to
the garage (or a nearby heated area) then the wiring would be much
shorter and there would be no electrical wiring in the sump at all-no
safety problems.
| |
| lp13-30 2008-01-31, 1:25 pm |
| FWIW, most central air conditioners now use a single pole contactor and
only break one leg of the 240 to the compressor. I have little
experience with well pumps, but what you have should work ok, and I
would imagine is common. One thing that should work would be to get a 2
pole contactor with a 240 volt coil and use it to break the 240 to the
pump, and put the pressure switch in series with the contactor coil.
Another advantage to this would be that I would imagine pressure
switches cost several times more than a contactor, and are harder to
replace, so the contacts on the pressure switch should last
indefinitely, and the contactor could be replaced when the points burn.
Larry
| |
| gfretwell@aol.com 2008-01-31, 1:25 pm |
| On Thu, 31 Jan 2008 05:48:07 -0600, letterman@invalid.com wrote:
>I guess this would be the solution and would not be that hard to wire,
>but is it really necessary?
The means of disconnect needs to open both legs but a switch only used
for control can open one.
You should have a "disconnect" within sight of the well head.
| |
|
| No, the current is the same through both legs, it doesn't matter in
that regard whether you switch one or both. But you do want to switch
both off if you ever need to service anything as if only one leg is
switched off, the other will be live with respect to ground, therefore
possible hazard.
nate
On Jan 31, 7:19=A0am, "RBM" <r...@noemail.com> wrote:
> For safety, you want a disconnect to kill both legs of the feed. For the
> operation of the pump, using both poles of the pressure switch pulls less
> current per pole, so the switch will last longer. Depending upon the HP of=
> the pump and =A0switch, this may not be that important. You can also insta=
ll
> jumpers in the pressure switch so the two poles work together to close the=
> one circuit.
>
>
>
> <letter...@invalid.com> wrote in messagenews:fnscj7$atn$1@aioe.org...
>
>
[color=darkred]
>
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>
>
>
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>
>
>
> - Show quoted text -
| |
|
| N8N wrote:
> No, the current is the same through both legs, it doesn't matter in
> that regard whether you switch one or both. But you do want to switch
> both off if you ever need to service anything as if only one leg is
> switched off, the other will be live with respect to ground, therefore
> possible hazard.
....
Agree. I'd have to go look to make sure I'm remembering correctly, but
I'm pretty sure on the one here there are double-pole contacts on the
pressure switch -- all that would be required in that case would be to
land the other side there as well to provide a total break to the pump.
But, in the situation it wouldn't help too much if it floods in an
accident scenario like described above anyway--the hot side would still
be submerged. Maybe not a dead short, but not something you'd want to
just stick your hand into...
I'd be looking to move the switch as another person said when it warmed
up I think--either on a riser to get it above the potential flood line
or remote.
--
| |
|
| I don't exactly know what you're saying. I'm saying : instead of breaking
the one leg through one pole of the pressure switch, use jumpers, and break
it through both poles, effectively doubling the switch capacity. You're
pulling the same current, but now it's going through two switches
simultaneously
"N8N" <njnagel@hotmail.com> wrote in message
news:a1649396-1278-4ffb-864d-51d4be879210@s8g2000prg.googlegroups.com...
No, the current is the same through both legs, it doesn't matter in
that regard whether you switch one or both. But you do want to switch
both off if you ever need to service anything as if only one leg is
switched off, the other will be live with respect to ground, therefore
possible hazard.
nate
On Jan 31, 7:19 am, "RBM" <r...@noemail.com> wrote:
> For safety, you want a disconnect to kill both legs of the feed. For the
> operation of the pump, using both poles of the pressure switch pulls less
> current per pole, so the switch will last longer. Depending upon the HP of
> the pump and switch, this may not be that important. You can also install
> jumpers in the pressure switch so the two poles work together to close the
> one circuit.
>
>
>
> <letter...@invalid.com> wrote in messagenews:fnscj7$atn$1@aioe.org...
>
>
>
>
>
>
>
>
>
> - Show quoted text -
| |
|
| yes, in series. If the motor draws 10A and you break one leg, that
one contact will be breaking 10A. If you break both legs, both
contacts will be breaking 10A. In actual practice, if there is any
sparking etc. it will be at whichever of the pair of contacts
mechanically opens first.
nate
On Jan 31, 1:10=A0pm, "RBM" <r...@noemail.com> wrote:
> I don't exactly know what you're saying. I'm saying : instead of breaking
> the one leg through one pole of the pressure switch, use =A0jumpers, and b=
reak
> it through both poles, effectively doubling the switch capacity. You're
> pulling the same current, but now it's going through two switches
> simultaneously
>
> "N8N" <njna...@hotmail.com> wrote in message
>
> news:a1649396-1278-4ffb-864d-51d4be879210@s8g2000prg.googlegroups.com...
> No, the current is the same through both legs, it doesn't matter in
> that regard whether you switch one or both. =A0But you do want to switch
> both off if you ever need to service anything as if only one leg is
> switched off, the other will be live with respect to ground, therefore
> possible hazard.
>
> nate
>
> On Jan 31, 7:19 am, "RBM" <r...@noemail.com> wrote:
>
>
>
[color=darkred]
s[color=darkred]
of[color=darkred]
l[color=darkred]
he[color=darkred]
>
>
>
>
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> - Show quoted text -
| |
|
| He, for whatever reason only has the ability to break one leg. Currently he
is breaking it through one pole of a two pole switch. I'm saying to install
jumpers in the switch and break the one leg through both poles
simultaneously to increase the switching capacity of the contacts. Pressure
switches are designed to open all contacts simultaneously
"N8N" <njnagel@hotmail.com> wrote in message
news:f1a23a8c-e042-4ff3-8c17-5b1e56749da0@i12g2000prf.googlegroups.com...
yes, in series. If the motor draws 10A and you break one leg, that
one contact will be breaking 10A. If you break both legs, both
contacts will be breaking 10A. In actual practice, if there is any
sparking etc. it will be at whichever of the pair of contacts
mechanically opens first.
nate
On Jan 31, 1:10 pm, "RBM" <r...@noemail.com> wrote:
> I don't exactly know what you're saying. I'm saying : instead of breaking
> the one leg through one pole of the pressure switch, use jumpers, and
> break
> it through both poles, effectively doubling the switch capacity. You're
> pulling the same current, but now it's going through two switches
> simultaneously
>
> "N8N" <njna...@hotmail.com> wrote in message
>
> news:a1649396-1278-4ffb-864d-51d4be879210@s8g2000prg.googlegroups.com...
> No, the current is the same through both legs, it doesn't matter in
> that regard whether you switch one or both. But you do want to switch
> both off if you ever need to service anything as if only one leg is
> switched off, the other will be live with respect to ground, therefore
> possible hazard.
>
> nate
>
> On Jan 31, 7:19 am, "RBM" <r...@noemail.com> wrote:
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> - Show quoted text -
| |
| .p.jm@see_my_sig_for_address.com 2008-02-02, 1:25 pm |
| On Thu, 31 Jan 2008 09:55:47 -0600, LP1330@webtv.net (lp13-30) wrote:
>FWIW, most central air conditioners now use a single pole contactor and
>only break one leg of the 240 to the compressor. I have little
>experience with well pumps, but what you have should work ok, and I
>would imagine is common. One thing that should work would be to get a 2
>pole contactor with a 240 volt coil and use it to break the 240 to the
>pump, and put the pressure switch in series with the contactor coil.
>Another advantage to this would be that I would imagine pressure
>switches cost several times more than a contactor, and are harder to
>replace, so the contacts on the pressure switch should last
>indefinitely, and the contactor could be replaced when the points burn.
>Larry
Thats pretty stupid advice. On a/c there is a SPECIFIC reason for only
breaking one side of the contactor...Too much info to explain here for
a DIY. Your dangerous!!
--
Click here every day to feed an animal that needs you today !!!
http://www.theanimalrescuesite.com/
Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'
'With sufficient thrust, pigs fly just fine.'
HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/
| |
| Chris Lewis 2008-02-05, 1:26 pm |
| According to <letterman@invalid.com>:
> I have a 220V submercible well pump. I am not going to even try to
> describe the location of the control box, pressure switch, etc. It's
> an odd situation because the pressure tank is in an underground
> concrete pit and the control box is in my garage, with the well
> outside in another location.
> Anyhow, because the wires were embedded into the conrete of the pit,
> and only used a 2 wire UF cable, I can only switch one side of the
> 220. Otherwise I'd have to do some major digging and concrete removal
> underground. The control box is wired correctly to the pump. It's
> just that the pressure switch only switches one side (pole) of the
> 220.
gfretwell is correct, you really only need (and it's legal) to switch
only one pole of the two for a 240V device, but the "disconnect" device
(breaker) needs to be two pole - so that all power is dead for servicing.
With 120V there's only one live wire, the other end is neutral (effectively
ground). With 240V there's two live wires, and no neutral.
With the pressure switch only switching one side, all power wires
are _still_ live, but with 120V only (except if you stick your fingers
across the pressure switch).
Having the pressure switch do both is nicer in some sense - if the
pressure switch is off, the well head and pump have no power. On the
other hand, if you did service on the system, and didn't kill the breaker,
having the pressure switch come on could zap you at a rather inopportune
moment with 240V if you were touching both poles.
However, I'm not very familiar with submersible control boxes. It was
my understanding that the pressure switch is _not_ in series with the
pump feed. The control box is switching the pump on and off, and the
pressure switch is only telling the control box _when_ to switch on and
off.
Which means, if you really want to do two-pole switching, it's in the
control box you have to do this, not the pressure switch, and the 2 wire
feed to the pressure switch doesn't have to be touched.
If you open up the control box and see one of the two poles (going to the
pump) go through the box, and the other simply wirenutted together, it
could simply be that you need to run the wirenutted poles through another
pair of terminals on the control box instead (if it has a vacant switch
pole and two terminals for it).
But, I wouldn't suggest you do that without a rather better understanding
of what the thing is doing. These control panels usually have a schematic
diagram that can help. The installation manual would be better still.
--
Chris Lewis,
Age and Treachery will Triumph over Youth and Skill
It's not just anyone who gets a Starship Cruiser class named after them.
| |
|
|
"Chris Lewis" <clewis@nortelnetworks.com> wrote in message
news:13qh6el4rb6m93@corp.supernews.com...
> According to <letterman@invalid.com>:
>
>
>
> gfretwell is correct, you really only need (and it's legal) to switch
> only one pole of the two for a 240V device, but the "disconnect" device
> (breaker) needs to be two pole - so that all power is dead for servicing.
> With 120V there's only one live wire, the other end is neutral
> (effectively
> ground). With 240V there's two live wires, and no neutral.
>
> With the pressure switch only switching one side, all power wires
> are _still_ live, but with 120V only (except if you stick your fingers
> across the pressure switch).
>
> Having the pressure switch do both is nicer in some sense - if the
> pressure switch is off, the well head and pump have no power. On the
> other hand, if you did service on the system, and didn't kill the breaker,
> having the pressure switch come on could zap you at a rather inopportune
> moment with 240V if you were touching both poles.
>
> However, I'm not very familiar with submersible control boxes. It was
> my understanding that the pressure switch is _not_ in series with the
> pump feed. The control box is switching the pump on and off, and the
> pressure switch is only telling the control box _when_ to switch on and
> off.
The pressure switch does go in series with the 240 volt circuit to the
control box. All the control box does, is contain the capacitor circuit, so
if the cap blows, it's easily replaced. It'll work just as well breaking
only one leg through the switch and running one directly to the control
>
> Which means, if you really want to do two-pole switching, it's in the
> control box you have to do this, not the pressure switch, and the 2 wire
> feed to the pressure switch doesn't have to be touched.
>
> If you open up the control box and see one of the two poles (going to the
> pump) go through the box, and the other simply wirenutted together, it
> could simply be that you need to run the wirenutted poles through another
> pair of terminals on the control box instead (if it has a vacant switch
> pole and two terminals for it).
>
> But, I wouldn't suggest you do that without a rather better understanding
> of what the thing is doing. These control panels usually have a schematic
> diagram that can help. The installation manual would be better still.
> --
> Chris Lewis,
>
> Age and Treachery will Triumph over Youth and Skill
> It's not just anyone who gets a Starship Cruiser class named after them.
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