I have a school project (Construction management) that involves the estimating of the electrical cost for a building addition. I can do the fixture counts, equipment hook ups, box counts, switches and etc. I cant figure out how much wiring would be involved. from the blueprints, is there a way to measure (estimate) the lf of wiring? this is a school building so there are mostly medsize room and hallways. any help would be great. I remember something about the homerun count from when i was a laborer, but could i figure 1 line around the room with a line for fixtures or something like that. doesnt have to be perfect by any means.
You aren't giving anything even close to enough info for an estimate.If you have set of plans you would have to go to the electrical specs. and find out what needs to be included. ie; additional panels,increased service from electric co., computer class rooms, fire alarm, wiring in conduit.the list goes on and on, your not just adding a few lights and outlets., what about HVAC that all requires elect. Good luck!
Figure out the load for each room. Remember the vacuum cleaner rule. Figure out where the source is (panel or sub). Then run each line (including upsdowns) to each outlets, add 2 feet at each outlet - add extra afterwards. Not sure with school codes for electrical, but say for kitchens, you need 2 sep circuits for the top, circ for fridge, circ for DW circ for GarDisp. etc. Each circuit starts a home run. You can probably find circuit requirements online somewhere. But If it really doesn't matter Put an outlet every 4 feet on the teacher wall. Use 2 circuits and stagger it. Use two more circuits and stagger them (vacuum) rule around the class room (maybe 2 for each wall). (New schools use WAY more power, elect smart boards, laptops, comps, etc). Just get the drawing, imagine what you'd want - draw the runs and add it up, otherwise use the plans. Just think, each circuit comes from the panel, over to the room, to the first outlet, then the next, (dont Y or branch out), and then the last circuit. It's clean, simple and easy. Wires comes easily purchasable in the following lengths from your favt box store. 50,100,250,1000
One way to go would be to identify the circuits in each room. Measure distance between outlets switches , add 12 for each outlet or fixture each 90deg turn if wire is to be run in conduit. If you have some idea of route wiring will take, account for going up over cielings or under floors to the home run to the service panel for each circuit , allow for a 6' tail at breaker location then add 10%. Assuming everything will take (or might be required to take ) perimeter routes w/ 90deg turns dressing the conduit on walls or racks you should be be safe. Some est runs will be long some short , but it evens out. Might be a good idea to show how you arrived at estimate on your worksheet. Might not be the only way to estimate , but it shows you gave it some thought. Best regards
I am an electrical contractor. I use the actual dimensions to estimate the wire. Copper wire is much to expensive to just take a guess. Start with the home-run and add the LF as you go. 1 circuit at a time. On a large commercial job I might figure a median length circuit and then use that figure for all other branch circuits.
