# Connecting RTU to Gen



## Almost Retired (Sep 14, 2021)

so the latest prints dont show the hook up for the gen?
probably why it wasnt done
do they show anything about what the current connected gen load is?
that would be an easy answer if they did

contacting the engineer who signed off on the prints may help
he may know that the gen wont carry that load along with what is already connected

it is possible your client was advised to add another gen for the rtu and they didnt want to do it
therefor you cant add it to the existing gen

follow the money it always reveals the truth


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## SWDweller (Dec 9, 2020)

I do not understand what your talking about. RTU does have a lot of different meanings.


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## canbug (Dec 31, 2015)

It's worth a phone call, someone has probably been paid for the rewire and it may be a missed deficiency. 
Don't get sucked in, right now you're just curious 😏 

Tim.


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## canbug (Dec 31, 2015)

😁


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## WronGun (Oct 18, 2013)

SWDweller said:


> I do not understand what your talking about. RTU does have a lot of different meanings.


It’s an isolated RTU/HVAC for a clean room which basically needs to stay at a certain temp and humidity level even during outages. 


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## CAUSA (Apr 3, 2013)

WronGun said:


> It’s an isolated RTU/HVAC for a clean room which basically needs to stay at a certain temp and humidity level even during outages.
> 
> 
> Sent from my iPhone using Tapatalk


Phase rotation to be confirmed before you do the switch will help in the transfer. they usually have phase monitoring built in them and will not turn on with only a flashing code. Depending on make and tonnage.

Is it gas heat or electric heat?

A data plate photo will help. I can send you the manual if I have it.

That unit will have a lot of filtration and sensors for air flow.

There should be fire sensors in the unit as well, but separate circuit.

Might also have a heat wheel for desiccant for humidity control and heat recovery depending on manufacture and tonnage.


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## WronGun (Oct 18, 2013)

I don’t know to be honest. 

Facilities showed me where the breaker was for the specific RTU and the gen panel with a list of all the loads on it where they want it moved to. 

It’s a great job but it’s another situation of needing more office time than I have. I may pass. 
Too much to figure out. It’s not like it’s a lighting circuit, they want a 480v, 100Amp circuit relocated 175’ to the gen panel room. 

The work isn’t an issue for me, it’s having to spend all this time investigating. 


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## WronGun (Oct 18, 2013)

It will bug me though. I may at least try to make a phone call. Even if I have to pay them to figure it out and take it off my hands. Exactly what I need in my life. I don’t have time for this, I just want the specs on a silver platter handed to me. 


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## joe-nwt (Mar 28, 2019)

WronGun said:


> It will bug me though. I may at least try to make a phone call. Even if I have to pay them to figure it out and take it off my hands. Exactly what I need in my life. I don’t have time for this, I just want the specs on a silver platter handed to me.
> 
> 
> Sent from my iPhone using Tapatalk


Then ask for it. Surely a 64,000 ² ft facility can get some engineering done.


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## paulengr (Oct 8, 2017)

I would monitor only. The vast majority of industrial grade generator controllers support CAN J1939 bus which gives you all the data conveniently. Otherwise you will probably be looking as basic discrete a like running, faulted, and maybe amps. With the CAN bus stuff you’ll get most of the sensor data. Since this is not a typical PLC protocol you will need a gateway converter. Anybus has some decent ones.


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## WronGun (Oct 18, 2013)

paulengr said:


> I would monitor only. The vast majority of industrial grade generator controllers support CAN J1939 bus which gives you all the data conveniently. Otherwise you will probably be looking as basic discrete a like running, faulted, and maybe amps. With the CAN bus stuff you’ll get most of the sensor data. Since this is not a typical PLC protocol you will need a gateway converter. Anybus has some decent ones.


Not familiar, this is a generator and an ATS. 

The last engineering firm I have listed did not plan the original design, but they drew up backup power layout for the recent retrofit of labs and equipment.(new circuits added to existing gen)

If they engineered this im betting they can tell me whether I can integrate the RTU into it. 

I’ll put some time into investigating it, I would like to get my foot in the door here. 

I suppose I need better direction on how to approach these jobs. Is my competition doing all these calculations ? Or do they just bring in engineers ? 


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## nrp3 (Jan 24, 2009)

Don’t put yourself in a position to be responsible for others failure to complete and the customer’s loss of product or productivity. Gracefully bow out if you aren’t completely sure of what you are doing. There is still plenty of work out there and plenty that won’t leave you wondering if this is going to cost me a bunch later on. I don’t like giving up either, but all the seat time may not yield anything other than loss of other simpler safer profits. Saying no is good thing, I should do it more.


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## WronGun (Oct 18, 2013)

nrp3 said:


> Don’t put yourself in a position to be responsible for others failure to complete and the customer’s loss of product or productivity. Gracefully bow out if you aren’t completely sure of what you are doing. There is still plenty of work out there and plenty that won’t leave you wondering if this is going to cost me a bunch later on. I don’t like giving up either, but all the seat time may not yield anything other than loss of other simpler safer profits. Saying no is good thing, I should do it more.


I hear what are you are saying. 
At the same time I remember being unsure of many things. I jumped into them regardless and by doing that I learned different types of systems. Which led me to being a shark in some of those markets. Bigger generators is something I want to get more of a grip on. I think of something like this as being an entry point. I’ll get to see how it’s all configured.

I spent the last 2 years of my career installing a massive generator system for a large hospital, I liked it. It’s not much of a learning experience when you have different crews working on different parts a 1/4 mile away from each other. 

The actual scope I’ve already figured out. I just need someone to run numbers. Maybe I just need a relationship with an engineering firm.
Not just to win this job but to understand the process for future jobs. I suppose I wouldn’t even think about it if they just asked for a lighting circuit. Seeing as it’s a 100A load with a gen panel full of primary transformer feeds and other misc. equipment this needs to be looked into. 

By process I mean would another electrical contractor walk in and spend this kind of time on calculations ? I suppose if the company is big enough they have in-house engineers or they simply hire a 3rd party. I’m a tiny company but I’m figuring on these particular jobs I’ll be competing against larger outfits. 


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## Southeast Power (Jan 18, 2009)

WronGun said:


> I’m a little thrown off on this one.
> 
> I’m looking at a 64,000 facility that was recently upfitted(maybe 6-8 months ago).
> 
> ...


what is your concern, the existing load and if the unit can handle the RTU?
If so, put a recorder on it or request data from a study.
I will typically take an amperage reading of the load side of the ATS to get a quick sample.
If its high or close to capacity, its a no go.
If there is the capacity you require, put a recorder on it for a week or so and let the data speak for itself. 

I love these type of jobs.
Im semi retired now, I could stop by and check it out for you.


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## WronGun (Oct 18, 2013)

Southeast Power said:


> what is your concern, the existing load and if the unit can handle the RTU?
> If so, put a recorder on it or request data from a study.
> I will typically take an amperage reading of the load side of the ATS to get a quick sample.
> If its high or close to capacity, its a no go.
> ...


Exactly, I like this stuff. So I’m Gunning for it. 

I’ve seen the fluke recorders I’ll check it out. 


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## RUSKES (6 mo ago)

Did you try TLA


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## paulengr (Oct 8, 2017)

Are you trying to integrate the distribution system or simply monitor generator status? Any control?

If it’s the distribution system some protective relays have communication. Otherwise there are always aux contacts. Breakers usually have DNP3 or Modbus if you are lucky. This allows direct networking with a PLC.

On the generator there are typically 3-4 systems involved. First there is the ATS. Some are quite stupid/useless. An ASCO can quite often supply a lot of data. On the generator controls there is generally speaking an engine controller/speed regulator and an AVR. The engine controllers give you a lot of information (battery voltage, fuel level, lots of status information, often Voltages and Currents). In contrast an AVR can often provide lots of electrical data but nothing on the engine side. The trick is that many of these devices have special protocols and need conversion. The trick is marrying them up.


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## WronGun (Oct 18, 2013)

Southeast Power said:


> what is your concern, the existing load and if the unit can handle the RTU?
> If so, put a recorder on it or request data from a study.
> I will typically take an amperage reading of the load side of the ATS to get a quick sample.
> If its high or close to capacity, its a no go.
> ...


That’s a pretty good investment though $4000 for a fluke. Maybe they’ll pay for it. 


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## WronGun (Oct 18, 2013)

paulengr said:


> Are you trying to integrate the distribution system or simply monitor generator status? Any control?
> 
> If it’s the distribution system some protective relays have communication. Otherwise there are always aux contacts. Breakers usually have DNP3 or Modbus if you are lucky. This allows direct networking with a PLC.
> 
> On the generator there are typically 3-4 systems involved. First there is the ATS. Some are quite stupid/useless. An ASCO can quite often supply a lot of data. On the generator controls there is generally speaking an engine controller/speed regulator and an AVR. The engine controllers give you a lot of information (battery voltage, fuel level, lots of status information, often Voltages and Currents). In contrast an AVR can often provide lots of electrical data but nothing on the engine side. The trick is that many of these devices have special protocols and need conversion. The trick is marrying them up.



I’m trying to calculate whether I can add this RTU to the generator panel without overloading. 











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## WronGun (Oct 18, 2013)

I suppose I can send the quote for the job with contingency in passing the study which will include another estimate for the actual study. That way I’m not wasting anytime. 


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## WronGun (Oct 18, 2013)

paulengr said:


> Are you trying to integrate the distribution system or simply monitor generator status? Any control?
> 
> If it’s the distribution system some protective relays have communication. Otherwise there are always aux contacts. Breakers usually have DNP3 or Modbus if you are lucky. This allows direct networking with a PLC.
> 
> On the generator there are typically 3-4 systems involved. First there is the ATS. Some are quite stupid/useless. An ASCO can quite often supply a lot of data. On the generator controls there is generally speaking an engine controller/speed regulator and an AVR. The engine controllers give you a lot of information (battery voltage, fuel level, lots of status information, often Voltages and Currents). In contrast an AVR can often provide lots of electrical data but nothing on the engine side. The trick is that many of these devices have special protocols and need conversion. The trick is marrying them up.


Can the ASCO tell you the load over a period of time or just the current load? 


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## nrp3 (Jan 24, 2009)

Don't not expand what you're doing either, but yes get the right tools to size these right. Inrush, load type, as well as total load is important. Watched someone have to put a larger alternator on a brand new generator because the fire pump just was too much. I'd like to grow into these some, but want a rock solid simple way to get a good grasp of existing loads and the effect of the new.


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## splatz (May 23, 2015)

Almost Retired said:


> so the latest prints dont show the hook up for the gen?
> probably why it wasnt done


This is true, the only question is whether the customer forgot to ask for it, or the engineer forgot to include it, but either way it's between the two of them. One way or another the normal resolution would be to have the stamped drawings corrected / modified. With the size of the facility and the clean room and all, you'd think they'd run a pretty tight ship and they'd want that stamp. 

If they don't, it's possible they're hoping not to call too much attention to the first clean room melt down, and are hoping they can get an electrician to quietly connect the RTU. Of course if there's a second outage and cleanroom meltdown there could be some angry owners firing people and hiring lawyers, wouldn't want to be around for that one. And eventually the power will go out again.


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## Wirenuting (Sep 12, 2010)

See if there is a generator log book sitting around. Hopefully someone has ran it on a recurring basis. If so it should show the running current of the generator over that past year or what ever. 
There is your base to see if you can carry that little RTU.
Im sure there is a building automation system that will control the start up of all the equipment. This way you move away from the inrush of everything starting at once.
Because that room is so tightly controlled, even a power bump will reset the program if they haven’t put it on a battery backup.
Beyond that, I would hope the ATS is sized to carry the full rated load of the generator. Asco is a good company and will work with their customers.

But I also think a call to the original engineer is a good idea. Liability is a killer.


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## WronGun (Oct 18, 2013)

ATS is also 400A. I may use a monitor device fluke 1537 over a 10-Day period if I can’t get any other info. 

These monitors are expensive, I see some websites rent them out, I may go that route. 

I’d say the job is mine, they accepted 2 other estimates for other jobs in the building I already sent in. 


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## CAUSA (Apr 3, 2013)

WronGun said:


> I’m trying to calculate whether I can add this RTU to the generator panel without overloading.
> 
> 
> 
> ...


There is a statistics page, but limited memory.

link to a series G controller. I cannot read the data in the photo.
The controller can do manual and automatic.



http://www.transferswitch4less.com/downloads/ASCO%20300G%20CONTROLLER%20OPERATORS.pdf



The HVAC unit will be at a low PF due to all the actuators and motors for air exchange and damper function. With compressor operation.
Say .8PF but this should be on the units data plate on the side wall or inside door panel.


the data logger is a good Idea for what on that panel now.

I would rent the logger for this and charge the customer for the investigation. For application feasibility.


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## paulengr (Oct 8, 2017)

WronGun said:


> Can the ASCO tell you the load over a period of time or just the current load?
> 
> 
> Sent from my iPhone using Tapatalk


Depends on the model. Some record kwhr. You’d have to look at the manuals. I’m not sure why this even matters. With generator sizing what you want us the peak even more than average load.


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## WronGun (Oct 18, 2013)

I will use a fluke 1736. I found one used from a retired industrial electrician for a little more than I charged for the rental. 

I’m going to monitor for 10-days, hopefully with fluke connect from the office. 


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## CAUSA (Apr 3, 2013)

WronGun said:


> I will use a fluke 1736. I found one used from a retired industrial electrician for a little more than I charged for the rental.
> 
> I’m going to monitor for 10-days, hopefully with fluke connect from the office.
> 
> ...


Make sure that generator alternator has the right capacity.

document the data plate.

could be the reason not hooked up in the first place.


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## nrp3 (Jan 24, 2009)

Are there other yearly variations that would change the reading ac vs heat via gas for instance? Does this rtu function as a heat pump too, or just gas heat and and ac?


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## WronGun (Oct 18, 2013)

nrp3 said:


> Are there other yearly variations that would change the reading ac vs heat via gas for instance? Does this rtu function as a heat pump too, or just gas heat and and ac?


This was entered as a note on data logging estimate. Further investigation of system required along with data logging. 


It just seems odd when they tell me “it just wasn’t done” the GC and his electrical contractor who did the Reno are big outfits, they used established engineers and architects. This is a decent chunk of of change carrying a 480V/100A3ph circuit 150’ away.

I’m not sure of the situation. The GC’s electricians aren’t usually the electricians the actual company brings in to attend to their specific needs, maintenance, etc. at least in my experience. 

Again the generator is existing and they engineered new circuits from the clean room Reno into it, no mention of an RTU in any of the Reno prints, or as-builts. 


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## WronGun (Oct 18, 2013)

There is already a decent load into the gen panel










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## Almost Retired (Sep 14, 2021)

i am betting on new gen required


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## CAUSA (Apr 3, 2013)

Or a separate one, strictly for the HVAC and transfer some of the load off of the existing one.

costing and availability is always the factor.

transfer switch and panel will be hard to get. I think I just talked myself out of that Idea.


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## WronGun (Oct 18, 2013)

I’m putting together another estimate for a new 45k. 30 week lead time. 

Another job I have sold (7) common 100Amp services. A simple meter socket with bypass 56 week lead time. 

This is getting annoying. How long do they need to catch up. I hear Milbank is having lots of trouble. 


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## just the cowboy (Sep 4, 2013)

WronGun said:


> There is already a decent load into the gen panel
> 
> 
> 
> ...


Yes I would go the route and install new.
The inrush of that many transformers will be large already with no way to shed it.


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## nrp3 (Jan 24, 2009)

I can't speak to the inrush of the transformers feeding those panels. If there is something to this (I don't know so please enlighten me, this is good discussion and why I come here.). I think, while the panel schedule is neat, it tells me little. What is pump 1,2,3? How much draw and inrush? What's in those other panels for loads? I think some sort of load study needs to be done. Otherwise, who knows? Liquid cooled generators are far out as far as lead time these days. They have caught up somewhat as far as the resi stuff goes.


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## WronGun (Oct 18, 2013)

nrp3 said:


> I can't speak to the inrush of the transformers feeding those panels. If there is something to this (I don't know so please enlighten me, this is good discussion and why I come here.). I think, while the panel schedule is neat, it tells me little. What is pump 1,2,3? How much draw and inrush? What's in those other panels for loads? I think some sort of load study needs to be done. Otherwise, who knows? Liquid cooled generators are far out as far as lead time these days. They have caught up somewhat as far as the resi stuff goes.


I just ordered a 45KW today 30 weeks. Larger probably longer. 

I would have to assume these larger jobs get engineering done. 

For this particular job I’m going to monitor and investigate the other panels, pumps, etc. Just looking at it, adding the RTU may push it. At the same time these RTU’s could be protected over 250%. Regardless, In-rush isn’t figured and would probably cut the Gen out. 

The only thing with monitoring only is you don’t know what being energized at any given time. If they don’t use a piece of equipment over the monitoring period it won’t calculate it. 

I think monitoring and overlooking connected loads might be a better bet. Otherwise, bring in an engineer. 


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## Almost Retired (Sep 14, 2021)

actually i suspect you just covered all an engineer could think to do
monitor and then go over the listed loads with a fine tooth comb.
obviously there may not be usage of all the possible loads so that they can be monitored
how ever, i get the impression this site could be at least slightly over engineered and redundant
meaning normal circumstances would not necessarily call for all three pumps at once, a power outage may not be a reason for them all, in fact it may be a reason for less load from the pumps ..... along with all other systems
i think along with every thing else you are doing you should simply wander around on a normal day and ask various ppl what they usually do on a normal day, how their systems operate and from that surmise the loads in the background that they are not really aware of but you as an electrician on the hunt are seeking and finding
keeping in mind that a normal day will not include a power outage
so a normal day for an outage should mean less load, not more
and of course the size of the gen already tells you that , but more can be learned by investigating


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## nrp3 (Jan 24, 2009)

My feeling was if in doubt go larger on the gen sizing. Not going to affect propane or natural gas units. May not be the best thing for the diesel.


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## Almost Retired (Sep 14, 2021)

every engine will have to run at the continuous rpm to maintain Hz
are you saying a light load at well above idle rpm would cause trouble?


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## oldsparky52 (Feb 25, 2020)

I'm a little late to this thread, and I sped read most of this so probably missed some stuff.

It seems to be that an engineer should be providing the missing information. The OP seems educated and experienced enough to do this engineering, but should not do it for a quote, if the OP does it, it should be for a fee, not for chance to do the work. Since it wasn't done originally, the OP must be carefull not to step in somebody else's mess. 

I would not walk away from this job. The best money making job I ever did I didn't really want, and threw a large number on it. When I got it I said "oh chit, now I've got to do it". Well, I made about $27,000 in a week.

Just don't take on responsibilities you are not paper qualified for and covered by insurance. 

AND, CHARGE LARGE FOR FIXING MISTAKES! 

Best of luck, and thanks for sharing these opportunities. I think I'd like to know the OP in real life. Sounds like a hell of a smart/successful guy.


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## Almost Retired (Sep 14, 2021)

in any thread, for any person
clik the dots on upper right
select only show this user

its an amazing short cut to catch up a little bit


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## oldsparky52 (Feb 25, 2020)

Almost Retired said:


> in any thread, for any person
> clik the dots on upper right
> select only show this user
> 
> its an amazing short cut to catch up a little bit


Thanks for that Jeff!!


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## CAUSA (Apr 3, 2013)

nrp3 said:


> My feeling was if in doubt go larger on the gen sizing. Not going to affect propane or natural gas units. May not be the best thing for the diesel.


Depending on the NA gas supply. it's a large building and hopefully the Gas utility company sized the meter and pressure to accommodate the extra load. If not, the Gas equipment in the building might see some loss of pressure and nuisance trip on flame failure.

Propane, well this is just a horizontal container that can be adjusted on the regulator, should not be a problem.

Diesel, If the customer is all in. The installation of an automatic resistive load bank to adjust on installed CT's. would solve a few things.

The wet stacking that the generator would experience running under loaded.

A better PF if high inductive loads are on the emergency backup system.

The ability to load test the generator during the periodic testing, with little change to the system.


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## Almost Retired (Sep 14, 2021)

CAUSA said:


> Depending on the NA gas supply. it's a large building and hopefully the Gas utility company sized the meter and pressure to accommodate the extra load. If not, the Gas equipment in the building might see some loss of pressure and nuisance trip on flame failure.
> 
> Propane, well this is just a horizontal container that can be adjusted on the regulator, should not be a problem.
> 
> ...


as well as provide some future load expansion room, if ever needed
which i can see being probable


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