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How many wires should be in a new thermostat cable?
Adding a C wire to a new Honeywell WIfi ThermostatHow can I wire my WIFI thermostat to control my millivolt fireplace?Need help adding a C wire for a wifi thermostatHow can I connect a WIFI thermostat to a Honeywell R845A switching relay?How to move from RH/RC thermostat to C thermostat in AC only system?How to wire A/C Thermostat given different wiring conventionsHow do a replace an old baseboard thermostat with a wifi thermostat?How should I hook up my WiFi thermostat given my current wiring situation?How to connect wifi thermostat with a boiler after cable upgrade?Do they make 24v transformers that have individual terminals for up to 4 thermostats?
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When roughing in thermostat wire, how many pair wire would you use to cover most thermostats?
I'm asking because keep seeing questions about C wire and wifi.
wiring thermostat thermostat-c-wire
add a comment |
When roughing in thermostat wire, how many pair wire would you use to cover most thermostats?
I'm asking because keep seeing questions about C wire and wifi.
wiring thermostat thermostat-c-wire
WiFi is actually quite the opposite - cuts down on the need for wires. But typical is a WiFi thermostat in the location of a regular thermostat - same number of wires as "normal". Also, unlike phone/ethernet/etc., thermostat wire is a bunch of separate wires, not actually pairs.
– manassehkatz
May 19 at 19:35
1
What is normal,? No less than 5.
– Robert Moody
May 19 at 23:08
1
@manassehkatz Same number plus one typically, for C.
– Harper
May 20 at 0:54
add a comment |
When roughing in thermostat wire, how many pair wire would you use to cover most thermostats?
I'm asking because keep seeing questions about C wire and wifi.
wiring thermostat thermostat-c-wire
When roughing in thermostat wire, how many pair wire would you use to cover most thermostats?
I'm asking because keep seeing questions about C wire and wifi.
wiring thermostat thermostat-c-wire
wiring thermostat thermostat-c-wire
edited May 19 at 19:29
isherwood
52.7k562137
52.7k562137
asked May 19 at 19:09
Robert MoodyRobert Moody
17711
17711
WiFi is actually quite the opposite - cuts down on the need for wires. But typical is a WiFi thermostat in the location of a regular thermostat - same number of wires as "normal". Also, unlike phone/ethernet/etc., thermostat wire is a bunch of separate wires, not actually pairs.
– manassehkatz
May 19 at 19:35
1
What is normal,? No less than 5.
– Robert Moody
May 19 at 23:08
1
@manassehkatz Same number plus one typically, for C.
– Harper
May 20 at 0:54
add a comment |
WiFi is actually quite the opposite - cuts down on the need for wires. But typical is a WiFi thermostat in the location of a regular thermostat - same number of wires as "normal". Also, unlike phone/ethernet/etc., thermostat wire is a bunch of separate wires, not actually pairs.
– manassehkatz
May 19 at 19:35
1
What is normal,? No less than 5.
– Robert Moody
May 19 at 23:08
1
@manassehkatz Same number plus one typically, for C.
– Harper
May 20 at 0:54
WiFi is actually quite the opposite - cuts down on the need for wires. But typical is a WiFi thermostat in the location of a regular thermostat - same number of wires as "normal". Also, unlike phone/ethernet/etc., thermostat wire is a bunch of separate wires, not actually pairs.
– manassehkatz
May 19 at 19:35
WiFi is actually quite the opposite - cuts down on the need for wires. But typical is a WiFi thermostat in the location of a regular thermostat - same number of wires as "normal". Also, unlike phone/ethernet/etc., thermostat wire is a bunch of separate wires, not actually pairs.
– manassehkatz
May 19 at 19:35
1
1
What is normal,? No less than 5.
– Robert Moody
May 19 at 23:08
What is normal,? No less than 5.
– Robert Moody
May 19 at 23:08
1
1
@manassehkatz Same number plus one typically, for C.
– Harper
May 20 at 0:54
@manassehkatz Same number plus one typically, for C.
– Harper
May 20 at 0:54
add a comment |
3 Answers
3
active
oldest
votes
For traditional Heat + Fan + AC systems, you need 4 for the system to work at all, and 5 if you want to support the C wire for smart 'stats.
However when you get into heat pump and multistage systems, just throw an 8 in there - it's readily available and not that much more expensive. You're not going to get very many latté's with the cost savings from using 4-wire.
I personally would run an 18/10 or 18/12 depending what was available to me, if I didn't already have some ENT roaming around the job that is ;)
– ThreePhaseEel
May 20 at 3:31
add a comment |
If you're building a new building and having new HVAC installed, I would simply put 1/2" conduit in the wall and be done. That way, you let the installer run the wire they need. I don't know that I would do this without at least consulting an HVAC installer to see where they would put the unit and the air return (typically the thermostat is as near the return as possible).
If you're going to just pre-run wire and dictate where the return will be and the HVAC unit will sit, I would run 18/5 wire if you know you will have a AC + gas heat, and 18/8 if you know you will have a heat pump (if you're in doubt, more will not hurt). Your most basic setup on most modern units needs 4 control wires plus the fifth blue "C" wire that provides power to the thermostat. It won't cover anything elaborate like a heat pump, but your greatest risk would be the installer uses your wire to pull the wire they actually need.
3
If running a cable instead of putting in conduit, I would err on the side of "extra". We're talking about literally just a few dollars for a typical run between 18/5 and 18/8. If the installer ends up needing more than a basic 5 wires, it will cost a lot more to fix it later.
– manassehkatz
May 19 at 19:34
1
Is extra bad? 5 seems to be ok 8 seems to cover the unknown.
– Robert Moody
May 19 at 20:08
2
@RobertMoody Not at all. Costs a bit more is all
– Machavity
May 19 at 21:46
add a comment |
I'd use 20/8 which is pretty standard today. That will cover anything up to a 2-stage heat pump system. I'm not sure how WiFi factors in here. An smart/electronic thermostat like a Nest does support WiFi but not between the HVAC unit and the thermostat.
When using 20/8 does it leave extra wires in case one gets nicked?
– Robert Moody
May 19 at 19:28
It's not common to run extra wires in anticipation of damage. If you expect it, run conduit.
– isherwood
May 19 at 19:30
Not so much anticipation of damage.But for the future.
– Robert Moody
May 19 at 19:38
2
"FOR THE FUTURE", RUN CONDUIT NOW. Conduit is the most future-proof technology there is for wiring. Pull out the obsolete, pull in the up to date, done.
– Ecnerwal
May 19 at 21:07
add a comment |
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3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
For traditional Heat + Fan + AC systems, you need 4 for the system to work at all, and 5 if you want to support the C wire for smart 'stats.
However when you get into heat pump and multistage systems, just throw an 8 in there - it's readily available and not that much more expensive. You're not going to get very many latté's with the cost savings from using 4-wire.
I personally would run an 18/10 or 18/12 depending what was available to me, if I didn't already have some ENT roaming around the job that is ;)
– ThreePhaseEel
May 20 at 3:31
add a comment |
For traditional Heat + Fan + AC systems, you need 4 for the system to work at all, and 5 if you want to support the C wire for smart 'stats.
However when you get into heat pump and multistage systems, just throw an 8 in there - it's readily available and not that much more expensive. You're not going to get very many latté's with the cost savings from using 4-wire.
I personally would run an 18/10 or 18/12 depending what was available to me, if I didn't already have some ENT roaming around the job that is ;)
– ThreePhaseEel
May 20 at 3:31
add a comment |
For traditional Heat + Fan + AC systems, you need 4 for the system to work at all, and 5 if you want to support the C wire for smart 'stats.
However when you get into heat pump and multistage systems, just throw an 8 in there - it's readily available and not that much more expensive. You're not going to get very many latté's with the cost savings from using 4-wire.
For traditional Heat + Fan + AC systems, you need 4 for the system to work at all, and 5 if you want to support the C wire for smart 'stats.
However when you get into heat pump and multistage systems, just throw an 8 in there - it's readily available and not that much more expensive. You're not going to get very many latté's with the cost savings from using 4-wire.
answered May 20 at 0:55
HarperHarper
81.1k555162
81.1k555162
I personally would run an 18/10 or 18/12 depending what was available to me, if I didn't already have some ENT roaming around the job that is ;)
– ThreePhaseEel
May 20 at 3:31
add a comment |
I personally would run an 18/10 or 18/12 depending what was available to me, if I didn't already have some ENT roaming around the job that is ;)
– ThreePhaseEel
May 20 at 3:31
I personally would run an 18/10 or 18/12 depending what was available to me, if I didn't already have some ENT roaming around the job that is ;)
– ThreePhaseEel
May 20 at 3:31
I personally would run an 18/10 or 18/12 depending what was available to me, if I didn't already have some ENT roaming around the job that is ;)
– ThreePhaseEel
May 20 at 3:31
add a comment |
If you're building a new building and having new HVAC installed, I would simply put 1/2" conduit in the wall and be done. That way, you let the installer run the wire they need. I don't know that I would do this without at least consulting an HVAC installer to see where they would put the unit and the air return (typically the thermostat is as near the return as possible).
If you're going to just pre-run wire and dictate where the return will be and the HVAC unit will sit, I would run 18/5 wire if you know you will have a AC + gas heat, and 18/8 if you know you will have a heat pump (if you're in doubt, more will not hurt). Your most basic setup on most modern units needs 4 control wires plus the fifth blue "C" wire that provides power to the thermostat. It won't cover anything elaborate like a heat pump, but your greatest risk would be the installer uses your wire to pull the wire they actually need.
3
If running a cable instead of putting in conduit, I would err on the side of "extra". We're talking about literally just a few dollars for a typical run between 18/5 and 18/8. If the installer ends up needing more than a basic 5 wires, it will cost a lot more to fix it later.
– manassehkatz
May 19 at 19:34
1
Is extra bad? 5 seems to be ok 8 seems to cover the unknown.
– Robert Moody
May 19 at 20:08
2
@RobertMoody Not at all. Costs a bit more is all
– Machavity
May 19 at 21:46
add a comment |
If you're building a new building and having new HVAC installed, I would simply put 1/2" conduit in the wall and be done. That way, you let the installer run the wire they need. I don't know that I would do this without at least consulting an HVAC installer to see where they would put the unit and the air return (typically the thermostat is as near the return as possible).
If you're going to just pre-run wire and dictate where the return will be and the HVAC unit will sit, I would run 18/5 wire if you know you will have a AC + gas heat, and 18/8 if you know you will have a heat pump (if you're in doubt, more will not hurt). Your most basic setup on most modern units needs 4 control wires plus the fifth blue "C" wire that provides power to the thermostat. It won't cover anything elaborate like a heat pump, but your greatest risk would be the installer uses your wire to pull the wire they actually need.
3
If running a cable instead of putting in conduit, I would err on the side of "extra". We're talking about literally just a few dollars for a typical run between 18/5 and 18/8. If the installer ends up needing more than a basic 5 wires, it will cost a lot more to fix it later.
– manassehkatz
May 19 at 19:34
1
Is extra bad? 5 seems to be ok 8 seems to cover the unknown.
– Robert Moody
May 19 at 20:08
2
@RobertMoody Not at all. Costs a bit more is all
– Machavity
May 19 at 21:46
add a comment |
If you're building a new building and having new HVAC installed, I would simply put 1/2" conduit in the wall and be done. That way, you let the installer run the wire they need. I don't know that I would do this without at least consulting an HVAC installer to see where they would put the unit and the air return (typically the thermostat is as near the return as possible).
If you're going to just pre-run wire and dictate where the return will be and the HVAC unit will sit, I would run 18/5 wire if you know you will have a AC + gas heat, and 18/8 if you know you will have a heat pump (if you're in doubt, more will not hurt). Your most basic setup on most modern units needs 4 control wires plus the fifth blue "C" wire that provides power to the thermostat. It won't cover anything elaborate like a heat pump, but your greatest risk would be the installer uses your wire to pull the wire they actually need.
If you're building a new building and having new HVAC installed, I would simply put 1/2" conduit in the wall and be done. That way, you let the installer run the wire they need. I don't know that I would do this without at least consulting an HVAC installer to see where they would put the unit and the air return (typically the thermostat is as near the return as possible).
If you're going to just pre-run wire and dictate where the return will be and the HVAC unit will sit, I would run 18/5 wire if you know you will have a AC + gas heat, and 18/8 if you know you will have a heat pump (if you're in doubt, more will not hurt). Your most basic setup on most modern units needs 4 control wires plus the fifth blue "C" wire that provides power to the thermostat. It won't cover anything elaborate like a heat pump, but your greatest risk would be the installer uses your wire to pull the wire they actually need.
edited May 19 at 21:51
answered May 19 at 19:20
MachavityMachavity
9,01832043
9,01832043
3
If running a cable instead of putting in conduit, I would err on the side of "extra". We're talking about literally just a few dollars for a typical run between 18/5 and 18/8. If the installer ends up needing more than a basic 5 wires, it will cost a lot more to fix it later.
– manassehkatz
May 19 at 19:34
1
Is extra bad? 5 seems to be ok 8 seems to cover the unknown.
– Robert Moody
May 19 at 20:08
2
@RobertMoody Not at all. Costs a bit more is all
– Machavity
May 19 at 21:46
add a comment |
3
If running a cable instead of putting in conduit, I would err on the side of "extra". We're talking about literally just a few dollars for a typical run between 18/5 and 18/8. If the installer ends up needing more than a basic 5 wires, it will cost a lot more to fix it later.
– manassehkatz
May 19 at 19:34
1
Is extra bad? 5 seems to be ok 8 seems to cover the unknown.
– Robert Moody
May 19 at 20:08
2
@RobertMoody Not at all. Costs a bit more is all
– Machavity
May 19 at 21:46
3
3
If running a cable instead of putting in conduit, I would err on the side of "extra". We're talking about literally just a few dollars for a typical run between 18/5 and 18/8. If the installer ends up needing more than a basic 5 wires, it will cost a lot more to fix it later.
– manassehkatz
May 19 at 19:34
If running a cable instead of putting in conduit, I would err on the side of "extra". We're talking about literally just a few dollars for a typical run between 18/5 and 18/8. If the installer ends up needing more than a basic 5 wires, it will cost a lot more to fix it later.
– manassehkatz
May 19 at 19:34
1
1
Is extra bad? 5 seems to be ok 8 seems to cover the unknown.
– Robert Moody
May 19 at 20:08
Is extra bad? 5 seems to be ok 8 seems to cover the unknown.
– Robert Moody
May 19 at 20:08
2
2
@RobertMoody Not at all. Costs a bit more is all
– Machavity
May 19 at 21:46
@RobertMoody Not at all. Costs a bit more is all
– Machavity
May 19 at 21:46
add a comment |
I'd use 20/8 which is pretty standard today. That will cover anything up to a 2-stage heat pump system. I'm not sure how WiFi factors in here. An smart/electronic thermostat like a Nest does support WiFi but not between the HVAC unit and the thermostat.
When using 20/8 does it leave extra wires in case one gets nicked?
– Robert Moody
May 19 at 19:28
It's not common to run extra wires in anticipation of damage. If you expect it, run conduit.
– isherwood
May 19 at 19:30
Not so much anticipation of damage.But for the future.
– Robert Moody
May 19 at 19:38
2
"FOR THE FUTURE", RUN CONDUIT NOW. Conduit is the most future-proof technology there is for wiring. Pull out the obsolete, pull in the up to date, done.
– Ecnerwal
May 19 at 21:07
add a comment |
I'd use 20/8 which is pretty standard today. That will cover anything up to a 2-stage heat pump system. I'm not sure how WiFi factors in here. An smart/electronic thermostat like a Nest does support WiFi but not between the HVAC unit and the thermostat.
When using 20/8 does it leave extra wires in case one gets nicked?
– Robert Moody
May 19 at 19:28
It's not common to run extra wires in anticipation of damage. If you expect it, run conduit.
– isherwood
May 19 at 19:30
Not so much anticipation of damage.But for the future.
– Robert Moody
May 19 at 19:38
2
"FOR THE FUTURE", RUN CONDUIT NOW. Conduit is the most future-proof technology there is for wiring. Pull out the obsolete, pull in the up to date, done.
– Ecnerwal
May 19 at 21:07
add a comment |
I'd use 20/8 which is pretty standard today. That will cover anything up to a 2-stage heat pump system. I'm not sure how WiFi factors in here. An smart/electronic thermostat like a Nest does support WiFi but not between the HVAC unit and the thermostat.
I'd use 20/8 which is pretty standard today. That will cover anything up to a 2-stage heat pump system. I'm not sure how WiFi factors in here. An smart/electronic thermostat like a Nest does support WiFi but not between the HVAC unit and the thermostat.
answered May 19 at 19:16
jwh20jwh20
42614
42614
When using 20/8 does it leave extra wires in case one gets nicked?
– Robert Moody
May 19 at 19:28
It's not common to run extra wires in anticipation of damage. If you expect it, run conduit.
– isherwood
May 19 at 19:30
Not so much anticipation of damage.But for the future.
– Robert Moody
May 19 at 19:38
2
"FOR THE FUTURE", RUN CONDUIT NOW. Conduit is the most future-proof technology there is for wiring. Pull out the obsolete, pull in the up to date, done.
– Ecnerwal
May 19 at 21:07
add a comment |
When using 20/8 does it leave extra wires in case one gets nicked?
– Robert Moody
May 19 at 19:28
It's not common to run extra wires in anticipation of damage. If you expect it, run conduit.
– isherwood
May 19 at 19:30
Not so much anticipation of damage.But for the future.
– Robert Moody
May 19 at 19:38
2
"FOR THE FUTURE", RUN CONDUIT NOW. Conduit is the most future-proof technology there is for wiring. Pull out the obsolete, pull in the up to date, done.
– Ecnerwal
May 19 at 21:07
When using 20/8 does it leave extra wires in case one gets nicked?
– Robert Moody
May 19 at 19:28
When using 20/8 does it leave extra wires in case one gets nicked?
– Robert Moody
May 19 at 19:28
It's not common to run extra wires in anticipation of damage. If you expect it, run conduit.
– isherwood
May 19 at 19:30
It's not common to run extra wires in anticipation of damage. If you expect it, run conduit.
– isherwood
May 19 at 19:30
Not so much anticipation of damage.But for the future.
– Robert Moody
May 19 at 19:38
Not so much anticipation of damage.But for the future.
– Robert Moody
May 19 at 19:38
2
2
"FOR THE FUTURE", RUN CONDUIT NOW. Conduit is the most future-proof technology there is for wiring. Pull out the obsolete, pull in the up to date, done.
– Ecnerwal
May 19 at 21:07
"FOR THE FUTURE", RUN CONDUIT NOW. Conduit is the most future-proof technology there is for wiring. Pull out the obsolete, pull in the up to date, done.
– Ecnerwal
May 19 at 21:07
add a comment |
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WiFi is actually quite the opposite - cuts down on the need for wires. But typical is a WiFi thermostat in the location of a regular thermostat - same number of wires as "normal". Also, unlike phone/ethernet/etc., thermostat wire is a bunch of separate wires, not actually pairs.
– manassehkatz
May 19 at 19:35
1
What is normal,? No less than 5.
– Robert Moody
May 19 at 23:08
1
@manassehkatz Same number plus one typically, for C.
– Harper
May 20 at 0:54