Electrical and Truss Load Calculations

[Ro_Ja Boy]

I'm just about ready to submit plans for permitting, but have been told I need to get electrical and truss load calculations before doing so.

A) Is it an electrician that I need to do electrical load calcs?
B) Typically is it the electrician and truss companies planned to be used for the actual project that people use to get the calcs?

Reason I ask is that I have a meeting with one more GC Wednesday before I decide to just move forward as owner-builder, so am wondering if it makes sense to wait until after that to submit plans since they likely have subs for each that they will use.

Thanks

 

[Ro_Ja Boy]

Bump

 

[Ro_Ja Boy]

Bueller?

 

[scottydosnntkno]

I have never had to do an electrical load plan to get a building permit.

The electrical permit however will say # of 110 circuits, #240 circuits, # of breaker panels, etc with a cost attached to each

For the trusses, your building plans will just say pre engineered trusses 24” O.C and show the direction they run so the truss company knows what the architect planned for the roof line. Then you install them to the truss company prints, and the inspector usually double checks against their plans on the final rough that it’s braced properly.

 

[matt_i]

I would post a separate thread on the electrical forum for your load calculations.

I think if you did some google searching on "electrical load calculations" you'll arrive at a method to get thru it.

The truss design & build company will use "engineering software" that outputs a design which will receive a Professional Engineer "P.E." certification stamp at the end. All of the calculations are done internally, but their assumptions about roof loads, snow loads (right?) and wind loads are all specifically identified so it will meet local codes. If you give your overall design to the truss company they will typically quote on the trusses at no cost, thinking they will likely get the business later if they're competitive. For a symmetrical gable roof they just need the distance to the outside of the walls, and the roof pitch to get going. If you have mods like attic storage or scissor trusses the time to tell them is up front.

In my locality, which is not yours, I identified an "engineered roof system" at the time I submitted the plans. Just the basic pitch and shape of the building were noted to get my plans approved. However at the time of framing inspection, I was required to have the P.E. stamped plans on-site for the inspector to peruse. However they took the path of the honey badger.

 

[Norcal]

I have never had to do an electrical load plan to get a building permit.

The electrical permit however will say # of 110 circuits, #240 circuits, # of breaker panels, etc with a cost attached to each

For the trusses, your building plans will just say pre engineered trusses 24” O.C and show the direction they run so the truss company knows what the architect planned for the roof line. Then you install them to the truss company prints, and the inspector usually double checks against their plans on the final rough that it’s braced properly.

This is a question I have to ask, how can you have 110V, & 240V? Unless your in the UK where a transformer required is used to step down 240V to 110V for power tools on construction sites, each leg is 55V.

NEC uses 120 & 240V for calcs.

I concur that the truss mfg will provide the data that is required when the plans are submitted to plan check.

 

[driftpin]

I just had an electrical contractor replace my electrical service in my single family detached dwelling, the branch circuits stayed in-place, it's nearly all in conduit. What isn't in conduit is in armored cable. Of course for the scope of work, the load calcs were required, as I also had installed a sub-panel in a new outbuilding, a 1-car garage (limited by code as to size, wish it could be larger).

The house got a new weatherhead, meter can/outside main disconnect, multiple grounds and new inside branch circuit panel.

I had three 240 volt circuits run in the outbuilding. It's done in armored cable. Each wall got a 20 amp GFCI circuit (multiple duplex outlets), and exterior floodlighting on two.

I have never had to do an electrical load plan to get a building permit.
The electrical permit however will say # of 110 circuits, #240 circuits, # of breaker panels, etc with a cost attached to each

For the trusses, your building plans will just say pre engineered trusses 24” O.C and show the direction they run so the truss company knows what the architect planned for the roof line. Then you install them to the truss company prints, and the inspector usually double checks against their plans on the final rough that it’s braced properly.

 

[rburke65]

OMG yes......you can't possibly have 110 volts! That is SO I'm proper!