# 208V instead of 480V for RTU..



## B4T (Feb 10, 2009)

I am bidding on a job that calls for wiring (4) RTU.. (5) ton each..

The building has 277/480V service and I figured on using that voltage to wire the units..

Turns out I am competing against the plants EC and he is telling them to use 120/208 instead.. :blink:

I explained the lower voltage will cost them more money in materials.. but I have not heard what this guys reasons are..

Anyone come across this before..


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## HARRY304E (Sep 15, 2010)

B4T said:


> I am bidding on a job that calls for wiring (4) RTU.. (5) ton each..
> 
> The building has 277/480V service and I figured on using that voltage to wire the units..
> 
> ...


The lower voltage will cost them in consumption as well..:no:


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## TOOL_5150 (Aug 27, 2007)

B4T said:


> I am bidding on a job that calls for wiring (4) RTU.. (5) ton each..
> 
> The building has 277/480V service and I figured on using that voltage to wire the units..
> 
> ...


Could be getting the units for ridiculously cheap.

~Matt


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## TOOL_5150 (Aug 27, 2007)

HARRY304E said:


> The lower voltage will cost them in consumption as well..:no:


How? watts is watts watson...

~Matt


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## RomExpert (Mar 24, 2011)

HARRY304E said:


> The lower voltage will cost them in consumption as well..:no:


Do tell, Professor Hacky...I mean Harry. :laughing:


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## RomExpert (Mar 24, 2011)

B4T said:


> I am bidding on a job that calls for wiring (4) RTU.. (5) ton each..
> 
> The building has 277/480V service and I figured on using that voltage to wire the units..
> 
> ...


If you have 480 in the building it would be absolute stupidity to run them on 208. Makes no sense whatsoever unless they got a good deal on some used units.


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## B4T (Feb 10, 2009)

RomExpert said:


> If you have 480 in the building it would be absolute stupidity to run them on 208. Makes no sense whatsoever unless they got a good deal on some used units.


These are brand new units.. ordered any way needed..


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## HARRY304E (Sep 15, 2010)

TOOL_5150 said:


> How? watts is watts watson...
> 
> ~Matt


Because you would need bigger units to do the same job..:thumbsup:


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## RomExpert (Mar 24, 2011)

B4T said:


> These are brand new units.. ordered any way needed..


Then whoever is telling them to get 208 ones is clueless.


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## RomExpert (Mar 24, 2011)

HARRY304E said:


> Because you would need bigger units to do the same job..:thumbsup:


Harry, please tell us you understand Ohm's Law correctly. :blink:


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## B4T (Feb 10, 2009)

RomExpert said:


> Then whoever is telling them to get 208 ones is clueless.


I agree.. but he is _their_ man.. :blink::blink:


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## HARRY304E (Sep 15, 2010)

RomExpert said:


> Do tell, Professor Hacky...I mean Harry. :laughing:


How was your nap peter....Oh i mean RomExpert..:laughing:


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## HARRY304E (Sep 15, 2010)

RomExpert said:


> Harry, please tell us you understand Ohm's Law correctly. :blink:


How about your self...:laughing:


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## RomExpert (Mar 24, 2011)

B4T said:


> I agree.. but he is _their_ man.. :blink::blink:


Is there already an adequate 208V distribution system in place to handle the extra load?


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## TOOL_5150 (Aug 27, 2007)

HARRY304E said:


> Because you would need bigger units to do the same job..:thumbsup:


This has nothign to do with what you said "cost them in consumption" to me means "Use more electricity" Which, it would not.

~Matt


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## RomExpert (Mar 24, 2011)

HARRY304E said:


> Because you would need bigger units to do the same job..:thumbsup:



Increase voltage, decrease current. Decrease voltage, increase current. A 5 ton unit operating at any voltage uses the same amount of power.


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## RomExpert (Mar 24, 2011)

HARRY304E said:


> How was your nap peter....Oh i mean RomExpert..:laughing:


Didn't get one today. :yawn:


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## HARRY304E (Sep 15, 2010)

TOOL_5150 said:


> This has nothign to do with what you said "cost them in consumption" to me means "Use more electricity" Which, it would not.
> 
> ~Matt


Yes it would because you would need bigger units to do the same job...


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## RomExpert (Mar 24, 2011)

HARRY304E said:


> Yes it would because you would need bigger units to do the same job...



Seriously, what are you talking about? :blink: He said they are 5 ton units. How do they consume more power at a lower voltage?


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## B4T (Feb 10, 2009)

RomExpert said:


> Is there already an adequate 208V distribution system in place to handle the extra load?


I didn't even check out the 208V equipment.. felt is was a no brainer to use 480V...


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## TOOL_5150 (Aug 27, 2007)

HARRY304E said:


> Yes it would because you would need bigger units to do the same job...


A 5 ton unit is a 5 ton unit harry.. wtf dont you get?


~Matt


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## RomExpert (Mar 24, 2011)

B4T said:


> I didn't even check out the 208V equipment.. felt is was a no brainer to use 480V...


It's definitely a no-brainer. This makes no sense at all.


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## BBQ (Nov 16, 2010)

Give the customer the price both ways, 480 and 208, the price difference may be enough to convince them to order 480 units.

The real question in my mind is if there is an existing transformer with enough capacity to pick up some RTUs and if there is how much will the RTU start ups effect the other items run from that same transformer.

Bad move all around to use 208 units with 480 available.


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## BBQ (Nov 16, 2010)

B4T said:


> I am bidding on a job that calls for wiring (4) RTU.. (5) ton each..
> 
> The building has 277/480V service and I figured on using that voltage to wire the units..
> 
> ...





HARRY304E said:


> The lower voltage will cost them in consumption as well..:no:





HARRY304E said:


> Because you would need bigger units to do the same job..:thumbsup:





HARRY304E said:


> Yes it would because you would need bigger units to do the same job...


Oh Harry ...........

The power consumed will be very close to the same.


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## HARRY304E (Sep 15, 2010)

BBQ said:


> Oh Harry ...........
> 
> The power consumed will be very close to the same.


Yes i know ..I have to be wrong somtimes you know...:laughing:


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## B4T (Feb 10, 2009)

BBQ said:


> Give the customer the price both ways, 480 and 208, the price difference may be enough to convince them to order 480 units.
> 
> The real question in my mind is if there is an existing transformer with enough capacity to pick up some RTUs and if there is how much will the RTU start ups effect the other items run from that same transformer.
> 
> Bad move all around to use 208 units with 480 available.


I don't have the exact specs.. but everything is double going with 208V.. :blink:

I'm checking units on the Internet till I get the cut sheets from the HVAC guy.. just to get an idea of price difference


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## BBQ (Nov 16, 2010)

B4T said:


> I don't have the exact specs.. but everything is double going with 208V.. :blink:


Actually more than double, 208 is not half of 480.


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## TOOL_5150 (Aug 27, 2007)

BBQ said:


> Actually more than double, 208 is not half of 480.


it is to him.:jester:

~Matt


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## RomExpert (Mar 24, 2011)

Well since we have this all sorted out, this would be an excellent time to ask if you plan on using PVC boxes and scotckote to hook these up. :jester:


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## TOOL_5150 (Aug 27, 2007)

RomExpert said:


> Well since we have this all sorted out, this would be an excellent time to ask if you plan on using PVC boxes and scotckote to hook these up. :jester:


STFU AND GTFO TROLL

~Matt


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## RomExpert (Mar 24, 2011)

TOOL_5150 said:


> STFU AND GTFO TROLL
> 
> ~Matt


Ok tool boy. :thumbsup:


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## B4T (Feb 10, 2009)

BBQ said:


> Actually more than double, 208 is not half of 480.


I was looking at wire and conduit size.. not the actual numbers.. 

Now that brings up an interesting point.. can you increase the bid by 65% of the 480V. bid to get a price that would work for 208V??

I have never figured a job this way, but it does sound like it should work..


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## B4T (Feb 10, 2009)

TOOL_5150 said:


> STFU AND GTFO TROLL
> 
> ~Matt


Talking tough to a Troll.. don't you know any better by now.. :no:


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## RomExpert (Mar 24, 2011)

B4T said:


> Talking tough to a Troll.. don't you know any better by now.. :no:


You don't really think I'm a troll, do you?


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## TOOL_5150 (Aug 27, 2007)

B4T said:


> Talking tough to a Troll.. don't you know any better by now.. :no:


STFU AND GTFO isnt talking tough.. its a standard sentence around here. :thumbup:


~Matt


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## TOOL_5150 (Aug 27, 2007)

RomExpert said:


> You don't really think I'm a troll, do you?


PeterD 

~Matt


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## RomExpert (Mar 24, 2011)

TOOL_5150 said:


> PeterD


..is a useless hack. :thumbup:


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## HARRY304E (Sep 15, 2010)

RomExpert said:


> You don't really think I'm a troll, do you?



..:blink::laughing::laughing:


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## TOOL_5150 (Aug 27, 2007)

RomExpert said:


> ..is a useless hack. :thumbup:


And how would someone with 14 posts even know what im talking about? Troll.

~Matt


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## RomExpert (Mar 24, 2011)

TOOL_5150 said:


> And how would someone with 14 posts even know what im talking about? Troll.
> 
> ~Matt


Because Peter D is a legend. :thumbsup:


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## TOOL_5150 (Aug 27, 2007)

RomExpert said:


> Because Peter D is a legend. :thumbsup:


And you are a ****** :thumbsup:

~Matt


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## RomExpert (Mar 24, 2011)

TOOL_5150 said:


> And you are a ****** :thumbsup:


Thanks. :blink:


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## B4T (Feb 10, 2009)

BYE BYE.. :laughing::thumbup::laughing:


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## BBQ (Nov 16, 2010)

B4T said:


> I was looking at wire and conduit size.. not the actual numbers..


So you are looking at fake numbers? :laughing:




> Now that brings up an interesting point.. can you increase the bid by 65% of the 480V. bid to get a price that would work for 208V??


It would not, for example 200 amp copper conductors are more than twice the price of 100 amp.


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## B4T (Feb 10, 2009)

BBQ said:


> :
> It would not, for example 200 amp copper conductors are more than twice the price of 100 amp.


Looking at MC prices.. 10/3 is $1.65 ft. and 6/3 is $2.75 ft... the 65% number works..

$1.65 plus 65% = $2.72.. just a thought..

Labor price increases about 20%..


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## CTshockhazard (Aug 28, 2009)

I did a restaurant several years ago with a 480V 400A 3Ø service.

Both RTU's were spec'ed and sent as 208V 1Ø.

Gotta love it.


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## Jlarson (Jun 28, 2009)

I've done stuff like that before, only cause I knew stuff about the building and its electrical system that gave me an edge :whistling2:


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## mdfriday (May 14, 2007)

CTshockhazard said:


> I did a restaurant several years ago with a 480V 400A 3Ø service.
> 
> Both RTU's were spec'ed and sent as 208V 1Ø.
> 
> Gotta love it.


A lot of the ones I have seen, you set the voltage based on jumpers, etc. For instance, the carriers were factory wired for 480, we had 120/240 delta. Changed a couple jumpers, whala.


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## Shockdoc (Mar 4, 2010)

He's pulling a bidding trick to get you to overbid him, i lost one early this year to a plants EC when they had me bid a 120/208 service when in fact they got a 277/480 service.


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## CTshockhazard (Aug 28, 2009)

mdfriday said:


> A lot of the ones I have seen, you set the voltage based on jumpers, etc. For instance, the carriers were factory wired for 480, we had 120/240 delta. Changed a couple jumpers, whala.


Believe you me, I wish it would have been that easy.:thumbsup:


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## BBQ (Nov 16, 2010)

mdfriday said:


> A lot of the ones I have seen, you set the voltage based on jumpers, etc. For instance, the carriers were factory wired for 480, we had 120/240 delta. Changed a couple jumpers, whala.





CTshockhazard said:


> Believe you me, I wish it would have been that easy.:thumbsup:



I have done a ton of RTUs and I have NEVER seen an RTU that you could change the voltage from 208 to 480 _other than_ the control transformer itself.

The compressors are not usually dual voltage and while the fan motor might be dual voltage if you changed it from 480 to 208 the contactor would be too small for the higher current.


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## CTshockhazard (Aug 28, 2009)

BBQ said:


> I have done a ton of RTUs and I have NEVER seen an RTU that you could change the voltage from 208 to 480 _other than_ the control transformer itself.


Ah yes, the first thing I do when I open them up. I mostly deal with 208 and they never seem to come shipped on that tap.


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## mgraw (Jan 14, 2011)

I agree with BBQ. I don't know of a manufacturer that makes 240/480v compressors.
If I were the OP I would give a price both ways, 208v and 480v.
I had one job where 4-10 ton units were 480v and 4-5ton units were 208v. Same building. Had to install a transformer and panel for the 208v units.


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## retiredsparktech (Mar 8, 2011)

RomExpert said:


> If you have 480 in the building it would be absolute stupidity to run them on 208. Makes no sense whatsoever unless they got a good deal on some used units.


 I think some of this equipment is ordered by a purchasing agent that doesn't have a clue. When he was ordering the equipment, he probably looked at the panel in the office and saw 120/208. Probably a special order unit too. Try to undo that mistake.


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## Smoke (Feb 25, 2011)

mdfriday said:


> A lot of the ones I have seen, you set the voltage based on jumpers, etc. For instance, the carriers were factory wired for 480, we had 120/240 delta. Changed a couple jumpers, whala.


this must not be typical, we had the same thing happen a few years ago.
we had 208 available but the units were 150a ea. (@208) and 400' from the source.
they paid us to put xfmr's next to the units.


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## captkirk (Nov 21, 2007)

To sum it up...you get charged for KWH or Killowatt hours and not what volatage you are using....


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## jwjrw (Jan 14, 2010)

captkirk said:


> To sum it up...you get charged for KWH or Killowatt hours and not what volatage you are using....




In reality the 208 equipment will pull more amps but cost the same to run because like has been said you are billed off how many KW's you use.


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## jwjrw (Jan 14, 2010)

Almost every new smaller 480/277 powered commercial building we have done has used 208 for the a/c units. I could care less what the hvac guys install. Just make sure the cut sheet I was given is correct and we are golden. I am an electrician not a hvac guy. Any hvac decision should be left to the hvac company. Just wire what they set and get paid.....


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## BBQ (Nov 16, 2010)

jwjrw said:


> In reality the 208 equipment will pull more amps but cost the same to run because like has been said you are billed off how many KW's you use.



Gee, thanks, glad you explained it. :laughing:


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## jwjrw (Jan 14, 2010)

BBQ said:


> Gee, thanks, glad you explained it. :laughing:




I know you have reading comprehension issues so I figured I would post it in a language even you could understand.....:blink::laughing:


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## B4T (Feb 10, 2009)

I just tell my customers.. "you pay for demand'... when the question comes up if 220V is cheaper to operate than 110V..


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## mgraw (Jan 14, 2011)

jwjrw said:


> I could care less what the hvac guys install. Just make sure the cut sheet I was given is correct and we are golden. ........I am an electrician not a hvac guy.


As a HVAC guy the cost difference between a 208v versus a 480v is minimal. As an electrician the the price difference is much more. I have no problem with ME's specifying 208v units.


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## Smoke (Feb 25, 2011)

mgraw said:


> As a HVAC guy the cost difference between a 208v versus a 480v is minimal. As an electrician the the price difference is much more. I have no problem with ME's specifying 208v units.


its not a problem either way as long as they supply what you bid from the spec/print


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## Shorty Circuit (Jun 26, 2010)

TOOL_5150 said:


> How? watts is watts watson...
> 
> ~Matt


You lose energy due to the fact that the transformer isn't 100% efficient. Say it's 90%. Then 10% of the current the RTU draws is wasted heating the transformer. I've got this same problem right now. The tranformer available is only 30KVA but the NEHB panel is running out of spaces. Still I'd rather put in a sub panel than use up some of the 30 KVA on two 8kw RHUs at 208. If I have a couple of KWs of duct heaters I'll go for 208, sometimes a 1 or 2 hp EF but usually it's all 480. Except I've got this one old building that only has 208 incoming. All the mechanical equipment is 208. Might as well stick with 208 there. A step up transformer and panel for new Mech equip at 480 would cost more than the larger feeders at 208.


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## bobelectric (Feb 24, 2007)

Do your bid at 480 volts and see what happens. Looks likea third bid thing to me.


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## BBQ (Nov 16, 2010)

Shorty Circuit said:


> You lose energy due to the fact that the transformer isn't 100% efficient.


No kidding, thanks for the electrical 101 course. :laughing:

If you go back and read the thread Harry had been saying the 208 unit uses more power on it's own at 208 and he was not including transformer losses.


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## Shorty Circuit (Jun 26, 2010)

BBQ said:


> No kidding, thanks for the electrical 101 course. :laughing:
> 
> If you go back and read the thread Harry had been saying the 208 unit uses more power on it's own at 208 and he was not including transformer losses.


If it uses more power not counting transformer losses, then it is not the same size, not the same number of KW, not the same number of BTUH. However, it will use the same amount of energy, it will just satisfy the stat faster. 

You're welcome for the free lesson in EE 101. I'd give you a freebee in Thermo101 but that's in the mechanical engineering curriculum. :laughing:


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## jwjrw (Jan 14, 2010)

mgraw said:


> As a HVAC guy the cost difference between a 208v versus a 480v is minimal. As an electrician the the price difference is much more. I have no problem with ME's specifying 208v units.




As an electrician I don't care what you install. I get paid to connect what YOU the hvac PROFESSIONAL installs. If I have to install a transformer I just make more money. We do a lot of up fits. The hvac company always seems to use 3 phase condensing units and single phase heat. I have no idea why....


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## BBQ (Nov 16, 2010)

Shorty Circuit said:


> If it uses more power not counting transformer losses, then it is not the same size, not the same number of KW, not the same number of BTUH. However, it will use the same amount of energy, it will just satisfy the stat faster.


Again, no chit Mr brain.

That is what we have been telling Harry but don't let the facts get in your way. :whistling2:


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## BBQ (Nov 16, 2010)

jwjrw said:


> As an electrician I don't care what you install. I get paid to connect what YOU the hvac PROFESSIONAL installs. If I have to install a transformer I just make more money. We do a lot of up fits. The hvac company always seems to use 3 phase condensing units and single phase heat. I have no idea why....



To some extent yes, but if a customer of mine is being told stupid things by the HVAC company I will speak up and explain that it will make my bid higher.


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## Shorty Circuit (Jun 26, 2010)

BBQ said:


> To some extent yes, but if a customer of mine is being told stupid things by the HVAC company I will speak up and explain that it will make my bid higher.


BBQ, I find that the best thing about hitting my head against a brick wall is that it feels so good when I stop. No more free courses for you. It's a waste of time. Next time I'll charge you tuition for my pain and suffering. :laughing:


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## BBQ (Nov 16, 2010)

Shorty Circuit said:


> BBQ, I find that the best thing about hitting my head against a brick wall is that it feels so good when I stop. No more free courses for you. It's a waste of time. Next time I'll charge you tuition for my pain and suffering. :laughing:



I don't take courses from those that have little clue.

Your posts on this forum have long ago proved you only know enough to be dangerous.


This thread here http://www.electriciantalk.com/f5/painted-into-corner-14828/ pretty much killed any credibility you may have had here.


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## jwjrw (Jan 14, 2010)

BBQ said:


> To some extent yes, but if a customer of mine is being told stupid things by the HVAC company I will speak up and explain that it will make my bid higher.



Most cases we bid what was spec on the plans and install the wiring. If they spec single phase heat I plan on it being single phase. My main point was I really don't care what the hvac guy installs. If it cost more to hook up so be it. But I agree if the customer did not know it will increase our bid I would point it out too.


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## Shorty Circuit (Jun 26, 2010)

BBQ said:


> Your posts on this forum have long ago proved you only know enough to be dangerous.


Since on many projects I've worked on I not only get to say who can and can't bid but I usually have the final say over who gets a contract and what they must build, I guess from some people's point of view that makes me dangerous. Perhaps yours. :no:

Be afraid. Be very very afraid.


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## mgraw (Jan 14, 2011)

jwjrw said:


> As an electrician I don't care what you install. I get paid to connect what YOU the hvac PROFESSIONAL installs. If I have to install a transformer I just make more money. We do a lot of up fits. The hvac company always seems to use 3 phase condensing units and single phase heat. I have no idea why....


I don't spec the units, I install what is spec'd. Why MEs spec 208v when 480v is available is a mystery to me. 
Why HVAC guys in you area install 1ph heaters with 3ph condensers is another mystery unless they are small splits and the distributor doesn't stock the 3ph heaters. 
You would never "connect" a unit I installed because I would connect it myself.


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## BBQ (Nov 16, 2010)

mgraw said:


> You would never "connect" a unit I installed because I would connect it myself.


Where I am you would never connect a unit you installed.:no::laughing:


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## mgraw (Jan 14, 2011)

BBQ said:


> Where I am you would never connect a unit you installed.:no::laughing:


Why not? Your area has rules that say you can't connect units you install.


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## BBQ (Nov 16, 2010)

mgraw said:


> Why not? Your area has rules that say you can't connect units you install.


Few HVAC people in this area have the required electrical license to do that. To get an electrical license here takes about 4 years in the electrical trade. And electricians don't install HVAC here.


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## mgraw (Jan 14, 2011)

BBQ said:


> Few HVAC people in this area have the required electrical license to do that. To get an electrical license here takes about 4 years in the electrical trade. And electricians don't install HVAC here.


Here you need 5 years to be an EC. I have statewide electrical and hvac.


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## BBQ (Nov 16, 2010)

mgraw said:


> Here you need 5 years to be an EC. I have statewide electrical and hvac.


Cool. 

Here that would be odd to have both.


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