Shaking Head Over Specifications

Status
Not open for further replies.
infinity

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Can someone try to explain this to me? These are all 20 amp circuits feeding furniture partitions with a printer receptacle at each station. (Where's the bang your head against the wall emoji?)

HR Specfications.jpg
 
Exceeding code requirements due to the nature of the intended use? Expecting you to use multi-wire branch circuits? Avoiding voltage drop issues? Just guessing. Are these notes on an engineered plan-set?
 
Yes, this is from the engineered drawings. The conductors are already up-sized to #10 with a #8 neutral because they're in a common raceway, for a 20 amp circuit this seems like a waste of good money. If the run is over 85' the conductors are increased to #8 phase and #6 neutral.
 
"Two multi-wire networks" means exactly what? An MWBC with two hots? Two MWBC's with 2 or 3 hots? Does the engineer have stock in a copper producer??
 
infinity said:
Yes, this is from the engineered drawings. The conductors are already up-sized to #10 with a #8 neutral because they're in a common raceway, for a 20 amp circuit this seems like a waste of good money. If the run is over 85' the conductors are increased to #8 phase and #6 neutral.
Click to expand...
What's the total number of current carrying conductors in the raceway?
 
Yes, it's a terrible spec. But if you're bidding on it, everyone else is in the same boat. If you've already got the job, then you could perhaps propose something more reasonable (and logical).
 
Maybe he's concerned with harmonics and neutral currents not cancelling out in a 3 phase system. There were articles about requiring super neutrals on high harmonic circuits. But this seem just way overkill to me. If you size things for 60C ampacity but use 90C wire, there should be plenty of margin on the neutral. I can see upsizing from 12 to 10 if over 100 feet, but going to #8 just seems nuts unless there are really long.
 
Wow. Is there blue sealtite too? And people still used isolated ground receptacles? (its so rare I ever see those wired properly, then the utilization equipment ends up getting a second path to ground anyways -like isolated ground receptacles feeding devices mounted to a rack and the rack is bonded to normal ground)
 
infinity said:
Can someone try to explain this to me? These are all 20 amp circuits feeding furniture partitions with a printer receptacle at each station. (Where's the bang your head against the wall emoji?)

View attachment 2557273
Click to expand...

The spec is the spec no matter how dumb it can be. You can try issuing an RFI to deviate from it.
 
gadfly56 said:
What's the total number of current carrying conductors in the raceway? "Two multi-wire networks" means exactly what? An MWBC with two hots? Two MWBC's with 2 or 3 hots? Does the engineer have stock in a copper producer??
Click to expand...
I'm guessing about 15. I don't know what it means if I had to guess it's a 3-wire MWBC, 2 hots and 1 neutral. It's going to be installed as per the spec.
 
MyCleveland said:
I am not seeing that Tom….
Click to expand...
EMT is technically tubing not conduit but in the context of this spec. EMT is fine. Not sure where the engineering came from but the client is a foreign bank so maybe this is from their boilerplate. Does anyone know what a network is in the context of this document?
 
Is this a Fed project ?
This is something, a life time ago, we would price per plan and then provide a deduct for using #12 everywhere unless cct was over 150’.
If nothing else, forces EE to defend the spec.
 
MyCleveland said:
Is this a Fed project ?
This is something, a life time ago, we would price per plan and then provide a deduct for using #12 everywhere unless cct was over 150’.
If nothing else, forces EE to defend the spec.
Click to expand...
No, it's an office building with cubicles. I remember these crazy spec's from the 90's but in 2021 this is a waste of someone's money.
 
infinity said:
Where's the bang your head against the wall emoji?
Click to expand...
Here, borrow mine:
banghead.gif
 
MyCleveland said:
price per plan and then provide a deduct for using #12 everywhere unless cct was over 150’.
If nothing else, forces EE to defend the spec.
Click to expand...

IMHO this is the most sensible approach. If the customer has more money then sense, then take it and enjoy the profit.

If they care about money then it lets you submit a lower quote.

Though 'increase one wire gauge' doesn't quite mean what they think it means. Just because odd AWG sizes are uncommon doesn't mean one = 2.

Jon
 
Status
Not open for further replies.
Top