Hooking up machinery-very expensive

[bhanson]

Hello All- I am the electrician at a manufacturing plant where we have 50+ punch presses- we are moving our equipment into a brand new building, and we are running into a very expensive problem: Our punch presses vary in age, country of origin, and tonnage capacity, and most of the presses do not have amperage draw listed on their tags, and some have no tags at all. With all this being said, the contractor for our new facility has his electrical estimator come in to calculate our loads in order to quote all of the bus duct, plugs, drop sizes ect..............here comes the problem-------- The estimator says that he sized the drops for the "tagged" machines from the amperage listed on the tag,, however for all the rest of the machines (which have no amperage listed or no tag at all) he used the main breaker( or main fuses) as the substitute for "tag" information and sized the drops according to that. He then proceeded to add up all of the 50+ machine calculations for the main bus duct sizing and ended up with 2000 Amp bus duct-- All of this puts our electrical costs close to $400,000!!! I have several key questions: First- if a machine has no tag, what is the most proper way to size the drop?? I don't see this addressed in the code... my problem with this is that we rarely use 20% of the capacity of the machine, so MUST we size the drop from the breaker /fuses (as this is never really spelled out in the NEC or NFPA) or can we size these machines based on our normal usage?? Secondly, although we have 50 + machine , only a fraction of them run at the same time, so is there an allowance regarding bus sizing with this in mind?? Sorry for the lengthy post, but this is a very expensive predicament, and any "wiggle room" is worth savings to us- Bill

 

[iwire]

I have several key questions: First- if a machine has no tag, what is the most proper way to size the drop??

I don't think there is a proper code compliant way to determine what size circuit an unlabeled machine takes.

. my problem with this is that we rarely use 20% of the capacity of the machine, so MUST we size the drop from the breaker /fuses (as this is never really spelled out in the NEC or NFPA)

It is spelled out, we are supposed to follow the listing and or labeling of the machine and machines are required to be labeled.

(I understand, they are old machines, I get that. The NEC does not)

or can we size these machines based on our normal usage??

Not code compliantly that I know of and as an electrician I would not trust the customers estimation of % of power needed.

Secondly, although we have 50 + machine , only a fraction of them run at the same time, so is there an allowance regarding bus sizing with this in mind??

There is a code section allowing the larger of noncoincident loads to be used for calculation.

220.60 Noncoincident Loads. Where it is unlikely that
two or more noncoincident loads will be in use simultaneously,
it shall be permissible to use only the largest
load(s) that will be used at one time for calculating the total
load of a feeder or service.

That said, if you underestimate the number of loads used at the same time you will end up spending more to do it right than you would have in the first place.

I see that section aimed at say heating loads vs air conditioner loads.

It seems risky to try it with factory production equipment because if business picks up that feeder is not going to handle it and fail when you are at your busiest.

 

[kwired]

Hello All- I am the electrician at a manufacturing plant where we have 50+ punch presses- we are moving our equipment into a brand new building, and we are running into a very expensive problem: Our punch presses vary in age, country of origin, and tonnage capacity, and most of the presses do not have amperage draw listed on their tags, and some have no tags at all. With all this being said, the contractor for our new facility has his electrical estimator come in to calculate our loads in order to quote all of the bus duct, plugs, drop sizes ect..............here comes the problem-------- The estimator says that he sized the drops for the "tagged" machines from the amperage listed on the tag,, however for all the rest of the machines (which have no amperage listed or no tag at all) he used the main breaker( or main fuses) as the substitute for "tag" information and sized the drops according to that. He then proceeded to add up all of the 50+ machine calculations for the main bus duct sizing and ended up with 2000 Amp bus duct-- All of this puts our electrical costs close to $400,000!!! I have several key questions: First- if a machine has no tag, what is the most proper way to size the drop?? I don't see this addressed in the code... my problem with this is that we rarely use 20% of the capacity of the machine, so MUST we size the drop from the breaker /fuses (as this is never really spelled out in the NEC or NFPA) or can we size these machines based on our normal usage?? Secondly, although we have 50 + machine , only a fraction of them run at the same time, so is there an allowance regarding bus sizing with this in mind?? Sorry for the lengthy post, but this is a very expensive predicament, and any "wiggle room" is worth savings to us- Bill

NEC kind of assumes those tags, nameplates, etc. will last forever:roll:

Whoever is estimating this needs to put more time into investigating the actual load - and can likely do so at a much lower end cost. You can try telling them that if they won't do it you can find someone that will.

Motor driven machinery will almost always have branch circuit overcurrent device settings of at least 200 - 275% of rated full load current, maybe only 150-200% if fuses, just taking a look at supply conductor size is going to be somewhat of an indicator of what the actual load may be. It definitely will yield smaller feeders, service conductors, gear then going by breaker ratings will. Any load/demand data you may have from the existing installation may be helpful as well.

Or maybe get an engineer to design things and then let the estimator figure from that design - he is possibly just playing it safe from the design perspective this option puts the design on someone else but someone that is supposed to know what they are doing.

 

[david]

Hello All- I am the electrician at a manufacturing plant where we have 50+ punch presses- we are moving our equipment into a brand new building,

I assume the 50 + punch presses where operational in the old facility. What size service, feeders and branch circuits did the old facility have. How much new or additional equipment are you adding. As said there may not be enough information available to determine a code compliant way. But there seems that the facility should have data available to make a comparison.

 

[petersonra]

there is no reason you cannot make your own nameplate up that shows what the FLA of the machine is. It is not hard to calculate it. I don't blame the estimator for not wanting to do it though. it will take time he does not have in the job.

409.110 Marking. An industrial control panel shall be
marked with the following information that is plainly visible
after installation:

670.3 Machine Nameplate Data.
(A) Permanent Nameplate. A permanent nameplate shall
be attached to the control equipment enclosure or machine
and shall be plainly visible after installation

Note that it does not say who makes the nameplate up or who attaches it.

 

[mgookin]

Hello All- I am the electrician at a manufacturing plant where we have 50+ punch presses- we are moving our equipment into a brand new building, and we are running into a very expensive problem: Our punch presses vary in age, country of origin, and tonnage capacity, and most of the presses do not have amperage draw listed on their tags, and some have no tags at all. With all this being said, the contractor for our new facility has his electrical estimator come in to calculate our loads in order to quote all of the bus duct, plugs, drop sizes ect..............here comes the problem-------- The estimator says that he sized the drops for the "tagged" machines from the amperage listed on the tag,, however for all the rest of the machines (which have no amperage listed or no tag at all) he used the main breaker( or main fuses) as the substitute for "tag" information and sized the drops according to that. He then proceeded to add up all of the 50+ machine calculations for the main bus duct sizing and ended up with 2000 Amp bus duct-- All of this puts our electrical costs close to $400,000!!! I have several key questions: First- if a machine has no tag, what is the most proper way to size the drop?? I don't see this addressed in the code... my problem with this is that we rarely use 20% of the capacity of the machine, so MUST we size the drop from the breaker /fuses (as this is never really spelled out in the NEC or NFPA) or can we size these machines based on our normal usage?? Secondly, although we have 50 + machine , only a fraction of them run at the same time, so is there an allowance regarding bus sizing with this in mind?? Sorry for the lengthy post, but this is a very expensive predicament, and any "wiggle room" is worth savings to us- Bill

I would assume you have an engineer on the "brand new building" project. That engineer needs to figure out the loads. Once he knows the loads he can produce drawings. Once you have drawings you can get bids.

Did the cart get in front of the horse?

 

[jap]

I would assume you have an engineer on the "brand new building" project. That engineer needs to figure out the loads. Once he knows the loads he can produce drawings. Once you have drawings you can get bids.

Did the cart get in front of the horse?

My thoughts exactly.

JAP>

 

[rlundsrud]

When you say no tags, does this mean the motor itself has no data plate? If not, can you determine the HP rating of the motors? If you can find out the HP, you can derive the current draw. Lastly, can you group the machines, then connect one machine from each group and measure the load? I would also make certain the contractor is doing a proper load Calc rather than simply adding the loads as this would significantly change the total. And finally, get at least two other quotes from other contractors.

 

[iwire]

I would assume you have an engineer on the "brand new building" project. That engineer needs to figure out the loads. Once he knows the loads he can produce drawings. Once you have drawings you can get bids.

Did the cart get in front of the horse?

Did you read his post? :huh:

 

[Cow]

If it's a punch press, isn't it just a simple hydraulic pump along with a small control cabinet for running solenoid valves, etc? It shouldn't be terribly complicated to look at the pump HP and control cabinet and get a pretty accurate FLA for each machine. Being that there is quite a few machines with no plates, it'll take some legwork, but that's part of the job.

As for the engineer comment, I'm not sure why'd you'd need one just to tell you how many amps each machine takes and how large the buss duct needs to be. Any electrician that knows how to do a load calc can handle that.

 

[mgookin]

Did you read his post? :huh:

Sure did. He says they are building a brand new building and the contractor's estimator is saying it's going to be 4k amps. Where is the engineer? I can't speak for his state but around here that requires an engineer. That engineer needs to figure out what those loads are.

It sounds like they hired a contactor to build something that has not been designed and that they're relying on that contractor to tell them what they need.

 

[iwire]

Sure did. He says they are building a brand new building and the contractor's estimator is saying it's going to be 4k amps. Where is the engineer?

DOH!, I apologize.


I had to re-read the OPs post I thought (maybe assumed) he said engineer when he had said estimator.

I agree with you, at this level it should be an engineer not an estimator.

Again I apologize for busting on you.

 

[mgookin]

DOH!, I apologize.


I had to re-read the OPs post I thought (maybe assumed) he said engineer when he had said estimator.

I agree with you, at this level it should be an engineer not an estimator.

Again I apologize for busting on you.

No problem. I probably had (at least) one coming!

Enjoy the cool weather; hope that rain is easy on you.

 

[Fulthrotl]

If it's a punch press, isn't it just a simple hydraulic pump along with a small control cabinet for running solenoid valves, etc? It shouldn't be terribly complicated to look at the pump HP and control cabinet and get a pretty accurate FLA for each machine. Being that there is quite a few machines with no plates, it'll take some legwork, but that's part of the job.

As for the engineer comment, I'm not sure why'd you'd need one just to tell you how many amps each machine takes and how large the buss duct needs to be. Any electrician that knows how to do a load calc can handle that.

if they have fifty of them, usually you've got some real fossels in there......
80 ton press with a 10 hp motor, and a ginormous flywheel, made in europe in 1946, etc.
schematics in polish. good times.

punch presses never die, they just go to a new auction. i don't think i've ever hooked one
up that was younger than i was.

i've hooked up a fair bit of machine tools.... you need nameplate numbers, and normally
you can look that stuff up on the net, but not so much when all the stuff predates the net
by 30 or 40 years.

to the OP, as you are the sparky for this concern, i'd go to the powers that be, and have
them spring for a tool you will find invaluable: a fluke 345PQ

it isn't cheap. $2,700 to be exact. but, if the right answer is $2,700 and the wrong answer
is $400,000 tell your boss to suck it up and buy it. a spiffy doodle power analyzer would be
even more sexy, but they get to five figures pretty quickly. you don't need it.
you could also rent a power analyzer and logger for a month, for almost what that fluke will
cost to buy. and the critter will come in handy down the road.

make yourself up a spreadsheet, and start building your equipment data.

that tool will give you all the data you need, including watts, va, reactive power, power factor,
inrush, and will tell where tyranny will strike next in the world. it'll also log it over time, comes
with software, and can download it to your pc.

it'll do it on 3 phase with only one clamp on. it cheats a bit, but it's close enough to get you there.

pull all the data off the equipment, give it to the electrical engineer, and your full survey cost
$2,700 plus your time.

if you have progressive punches or hydros, it still doesn't change much. starting current, running current,
present the data to the engineer, let him put his name on it, put it out to bid, etc.

i'm assuming all this stuff is 460~480. with that in mind, bus duct gets pricey, and there are other ways
to skin a cat. you'd have to look at how much your plant will get reconfigured over time, but cable tray,
and strategically placed gear can work out better some times. folks are tending away from bus duct unless
there is gonna be constant reconfiguration.

 

[kwired]

Not all places would legally require this project to be designed by a licensed engineer, at least not for private enterprises as the owners. Here it still is subject to State Electrical Division and their laws - which ultimately means NEC does apply.

 

[Cow]

Not all places would legally require this project to be designed by a licensed engineer, at least not for private enterprises as the owners. Here it still is subject to State Electrical Division and their laws - which ultimately means NEC does apply.

I don't know how it is in other states, but it's my understanding that here in Oregon any one with a general supervisors(masters) license can engineer anything they are going to install. But, you can't engineer for a 3rd party, you are only allowed to engineer your own projects. I'd say 98% of our projects (ag, industrial) are designed by us, without a professional engineer).

 

[Fulthrotl]

I don't know how it is in other states, but it's my understanding that here in Oregon any one with a general supervisors(masters) license can engineer anything they are going to install. But, you can't engineer for a 3rd party, you are only allowed to engineer your own projects. I'd say 98% of our projects (ag, industrial) are designed by us, without a professional engineer).

and if it's something that has to go thru plan check, if you engineer it, or if a
PE engineers it shouldn't make all that much difference, but my experience
is that if a PE has a wet ink signature on it, it goes thru plan check much more
smoothly.

the last three large projects i have done, i've engineered completely, and when
i was done, my electrical engineer went over them, tuning them up a bit, asking
critical questions, and tuning a bit more, etc.

money well spent, imho.

if this project were in front of me to do, i'd be out there measuring draws on the
equipment, and sitting down, deciding what needed to be where, and how to connect
the dots, and once i had a rough drawing put together, and a schedule of loads to be
served, i'd be off to get it blessed by an engineer.

if something is found amiss later on, i did my due diligence. mistakes happen, and
the chance of two people making the SAME mistake isn't as great as me out there on my own.

i hate when my job description becomes "single point of failure".