Trace Out Circuits??

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Alwayslearningelec

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Okay, I went to visit a six story office space that is being renovated. A bunch of the panels are existing to remain as well as some lights etc. It is a patch and match type of job. One of the other guys there was saying the tracing of the circuits was going to be VERY time consuming. Could someone explain what tracing of circuits entails the electrician to do?

Thanks
 
If you do not have any as built drawings it will be time consuming. Then again I take as builts with a grain of salt and do not trust them 100%. If it is a large project mapping circuits can become adventagous when adding one outlet or light in a particular area. When tracing existing I usually go through and make sure everything is live. Then I kill circuits one by one and map them out with a tic tracer or by visually seeing which sets of lights quit working.
 
horsegoer said:
Okay, I went to visit a six story office space that is being renovated. A bunch of the panels are existing to remain as well as some lights etc. It is a patch and match type of job. One of the other guys there was saying the tracing of the circuits was going to be VERY time consuming. Could someone explain what tracing of circuits entails the electrician to do?

Thanks
Click to expand...
IMHO, I would think that tracing of circuits would entail at least the following:
  • determine the origin of the circuit (source)
  • determine the characteristics of the circuit. i.e. branch or feeder, nominal voltage, ocpd, conductor sizing
  • determine condition and usability of the circuit including breakers, devices and other components
  • determine if circuit is properly identified and if not, properly reidentify
  • determine overall ampacity of circuits and their effect on panelboards they're located within
  • etc., etc.
 
Well....for renovation purposes....you would trace ckt.s so that you know what conduit and wire goes where, and what it feeds. You would want to know this because if you intend to reuse some of the circuits/conduit runs/wiring, you have to know 1. Where it originates 2. Its capacities (conduit size, wire size) 3. Destination (where it goes to) 4. Routing (how it gets to where ever it is going)

All of this takes time. It always takes more time than you think it will.....especially in a old building, that has been renovated before.....Sometimes you are better to tear it all out and start over.:grin:...but usually you dont see it this way untill it is to late:rolleyes:.......ask me how I know how....:mad:
 
A typical office building originally has a designated number of circuits to service each area and many times these spaces are not builtout and the home runs area pulled to a certain junction box in the new building. As tenants spaces are built out these home runs are used to fill the new tenant's needs and if there are not enough, maybe circuits will be added by new raceways or re-pulled in the original home run raceway. Typically, these spaces expand and contract, and are many "times over" changed, with many different EC's and "fly by nighters" working in their ceilings! The original panel was designed with enough circuits on a "square footage bases", but the normal thing that happens is sub panels begin to fill the walls of the electrical room as new EC's enter the building installing expansions. Many circuits are overlooked in junction boxes throughout the floor. Where the original floor had a full floor of secretarial stations easily being supplied by a 42 circuit panel---ten years down the road---this same floor with four tenants BUT ALL having secretarial stations may have five panels with a total of 114 circuits, maybe more!! The main reason is improper engineering practice by buildout engineers or EC's ! As tenant spaces are designed, the engineering firms do not know what is existing and do not spend the time or money to find out. Many times the buildout plan will indicate a home run circuit with an arrow saying "TO EXISTING CIRCUIT" ? And then the EC shows up and he can't find an "existing circuit" -- so they just add a sub panel. For many contractors that do the demolition and identify the "GAINED" circuits there is a huge advantage in bidding the next buildout within that space. The cost of the panel and new homeruns can be saved. There should be a law against adding sub panels to some extent in my opinion!!! Now, consider among all these circuits and added circuits over this ten year period how many circuits are shared by two tenants????? This is where is gets expensive tracing circuits. You cannot identify a breaker with a tracer with 100% ashurity that it only feeds one tenant. Todays offices get very upset if you shutdown their computer by mistake!!! We used to go in extra early in the morning and get our circuits identified--then turn them back on just in case they were shared...
 
Often the low ball EC will just start a project. and just grab what circuits are live, and at times leave live circuits just laying where they are found, no planning, no tracing, just pure hack work, we all see it when we get in these projects, I had one fit up where it was a real mess, so I asked one of the other trades what happened here, he said the EC was the head of the local electrical assn, and did what he pleased, while telling everyone else to do good work, you will find all sorts of problems in buildings that go thru reguler fit-up work. Just do a good job and do it right, when you bid these jobs, you may want to do a walk thru with the owners and point out the scope involved, it helps when you present the project cost.
 
charlietuna said:
A typical office building originally has a designated number of circuits to service each area and many times these spaces are not builtout and the home runs area pulled to a certain junction box in the new building. As tenants spaces are built out these home runs are used to fill the new tenant's needs and if there are not enough, maybe circuits will be added by new raceways or re-pulled in the original home run raceway. Typically, these spaces expand and contract, and are many "times over" changed, with many different EC's and "fly by nighters" working in their ceilings! The original panel was designed with enough circuits on a "square footage bases", but the normal thing that happens is sub panels begin to fill the walls of the electrical room as new EC's enter the building installing expansions. Many circuits are overlooked in junction boxes throughout the floor. Where the original floor had a full floor of secretarial stations easily being supplied by a 42 circuit panel---ten years down the road---this same floor with four tenants BUT ALL having secretarial stations may have five panels with a total of 114 circuits, maybe more!! The main reason is improper engineering practice by buildout engineers or EC's ! As tenant spaces are designed, the engineering firms do not know what is existing and do not spend the time or money to find out. Many times the buildout plan will indicate a home run circuit with an arrow saying "TO EXISTING CIRCUIT" ? And then the EC shows up and he can't find an "existing circuit" -- so they just add a sub panel. For many contractors that do the demolition and identify the "GAINED" circuits there is a huge advantage in bidding the next buildout within that space. The cost of the panel and new homeruns can be saved. There should be a law against adding sub panels to some extent in my opinion!!! Now, consider among all these circuits and added circuits over this ten year period how many circuits are shared by two tenants????? This is where is gets expensive tracing circuits. You cannot identify a breaker with a tracer with 100% ashurity that it only feeds one tenant. Todays offices get very upset if you shutdown their computer by mistake!!! We used to go in extra early in the morning and get our circuits identified--then turn them back on just in case they were shared...
Click to expand...

If the design would be up to me, I would not not allow any branch circuits in the floor panel. I would require every tenant to have a subpanel in their suite.
 
I know the OP simply asked why trace but if we all agree it's necessary what is the easiest way?

I don't have one but I've seen the cable & sat guys attach a sender on the end of a cable and then go back to where the cables terminate. The senders are numbered and the receiver will tell which sender number is doing the "talking". Of course the circuits must be de-energized first.

Anyone tried these in electrical work?
 
We worked in some of the largest office high rise buildings. Understand that we had one tenant who rented five full floors, while other floors had eight or ten small tenants. These tenants are constantly expanding or contracting and when they outgrow their space, the management company would rent them their own floor-if necessary! The ability to provide this space is in their lease agreements and part of the reason they were paying over $38.00/Sq. foot for space. On one building we were the prime EC for probably ten years and that worked out good since we maintained "as builts" for each tenant, but as soon as other contractors started working in the building this standard was set aside.. Now thats not near as bad as the requirment to remove data cabling from ceilings where for years cables ran together with other tenants!!! Now thats a nightmare !!!
 
ohm said:
I know the OP simply asked why trace but if we all agree it's necessary what is the easiest way?

I don't have one but I've seen the cable & sat guys attach a sender on the end of a cable and then go back to where the cables terminate. The senders are numbered and the receiver will tell which sender number is doing the "talking". Of course the circuits must be de-energized first.

Anyone tried these in electrical work?
Click to expand...

Oh boy, yes I use them, and often I can't do without them. Depending on how much $$$ you have, you can buy a trace toner that can be used on hot circuits. READ THE OWNERS MANUAL FIRST TO BE SURE!!! The bulk of my experience is process controls and automation, so I have all kinds of neat little tools (toys, as my wife calls them). Money spent on the right tools can sure make the job quicker and easier.
 
we do work for lockheed martin and they required us to label every single receptacle, circuit, wire in junction boxes in celings and anything else. there was probably about 100 full panels in the building, thousands of receptacles and so many junction boxes. it taken us about a month to do it. we had to buy 2, 1000 dollar tracers to do it
 
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