I don't.
Where are you all getting your information about it having to be attached to to be considered a mast?
JAP>
The use of EMT as a service mast
- Thread starter randyheggem
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I don't.
Where are you all getting your information about it having to be attached to to be considered a mast?
JAP>
Like my description earlier, is a mast on a sailboat only considered a mast when supporting the sails?
I think not, I think that long pole sticking up out of the middle of a sailboat is a mast regardless of whether the sails are up or down.
If not, it needs to be called a mast for the simple reason it sounds much cooler.
If you've installed a mast for other than service applications, why did you call it a "mast" ? out of habit ? or was there something somewhere that says the pipe you installed up in the air was definitely a "mast" ?
Why would you need to suffer the expense of a rigid conduit if it's not supporting the load of anything unless the power company requires it that is?
I agree with you all on the whole mast vs. riser thing, but, the OP was asking where does it say you cant use EMT as a service mast.
I think the better question would be, can EMT be used as a raceway for service conductors.
If the answer is yes, then there is no reason that EMT cannot be used for the raceway coming out of the top of a meter base.
At that point you would need to know if the service drop is actually going to be attaching to it or not, and, if so, then the rules for strength and support kick in.
If not used as a means of support, I don't see why EMT couldn't be used as the raceway for the service riser or mast or whatever you want to call it.
JAP>
kwired
Electron manager
- Location
- NE Nebraska
"Service Masts as Supports" is all that NEC addresses. Though they probably should change or add wording to include any raceway supporting any overhead conductor runs. Like I said before I have installed or encountered other situations where a raceway was supporting overhead conductors at times.
kwired
Electron manager
- Location
- NE Nebraska
we both posted at about same time, but I agree. NEC should maybe word it as raceways supporting overhead conductor runs or something of that nature, and be inclusive of all overhead conductor runs and not just service drops.Like my description earlier, is a mast on a sailboat only considered a mast when supporting the sails?
I think not, I think that long pole sticking up out of the middle of a sailboat is a mast regardless of whether the sails are up or down.
If not, it needs to be called a mast for the simple reason it sounds much cooler.
If you've installed a mast for other than service applications, why did you call it a "mast" ? out of habit ? or was there something somewhere that says the pipe you installed up in the air was definitely a "mast" ?
Why would you need to suffer the expense of a rigid conduit if it's not supporting the load of anything unless the power company requires it that is?
I agree with you all on the whole mast vs. riser thing, but, the OP was asking where does it say you cant use EMT as a service mast.
I think the better question would be, can EMT be used as a raceway for service conductors.
If the answer is yes, then there is no reason that EMT cannot be used for the raceway coming out of the top of a meter base.
At that point you would need to know if the service drop is actually going to be attaching to it or not, and, if so, then the rules for strength and support kick in.
If not used as a means of support, I don't see why EMT couldn't be used as the raceway for the service riser or mast or whatever you want to call it.
JAP>
- Location
- Illinois
- Occupation
- retired electrician
The same rule as in 230.28, also appears in 225.17 to cover overhead runs that are not service conductors, and both sections only apply where the "mast" is being used to support conductors or cables.
A change to "raceways" would not be appropriate as there is no requirement that the supporting mast be a raceway. For example temporary services in my area most often use a 4x4 as the mast to support the overhead service conductors.
Another interesting take on the word mast, and, all the more reason using the word "mast" is deceiving.
Again, picturing that, the 4x4 is described as a "mast" because it's the part that's sticking up in the air.
If we are going to call a 4x4 a mast just because it supports overhead service conductors , why would that be any different than a bracket that may be built above a roof line to support an EMT "mast" above the roof, but, the service conductors were attached and supported by the bracket instead of the EMT ?
Does the bracket now magically become a "mast" just because the service conductors may have attached to it?
I say no.
JAP>
- Location
- Illinois
- Occupation
- retired electrician
So write and submit a Public Input with a definition that will work for the application of the NEC.
However, I expect the panel's response will be that "mast" is a commonly understood word and does not need to be defined in the NEC.
The official dictionary for the NEC for terms that are not defined in the NEC or other building codes it the Merriam_Webster Collegiate Dictionary, 11th Edition, but I don't have a cope and don't know how it is defined in that dictionary.
Can EMT be used as a service mast as long as it's not used to support service conductors?
JAP>
- Location
- Illinois
- Occupation
- retired electrician
mtnelect
HVAC & Electrical Contractor
- Location
- Southern California
- Occupation
- Contractor, C10 & C20 - Semi Retired
Our family had a 45-foot sailboat (Javalin) moored in a slip in Maria Del Ray with Los Angeles Athletic Club next to the Warehouse Restaurant, we had a mast.
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mtnelect
HVAC & Electrical Contractor
- Location
- Southern California
- Occupation
- Contractor, C10 & C20 - Semi Retired
Any sailors out there ?
I can't speak for everyone, but, after this thread, the electricians I know, who also own sailboats, are probably out busy trying to redefine just exactly what that long tubular object is protruding out of the middle of their vessels ,,,,
JAP>
kwired
Electron manager
- Location
- NE Nebraska
I don't see why it can't support the service the service drop, if it is strong enough to withstand the strain imposed on it, it is POCO's and some AHJ's that impose a rule requiring RMC. NEC as written just says it needs to be able to withstand the conditions.
A majority of service drops - that might mean RMC is likely a wise choice, but what if you had only a 10 to 20 foot span? That does happen occasionally.
Some POCO's or AHJ's also dictate minimum of 2" RMC regardless the conditions. I've seen or installed a few that are only 1.5" or 1.25"
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Yes it is. That drawing was around when I started in WA in 78
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
EMT is not allowed in WA for service entrance conductors, Dennis posted the drawing on masts we go by
Which would make sense seeing as how both of those details show the service drop attached to the mast.
Jap.
Another C10
Electrical Contractor 1987 - present
- Location
- Southern Cal
- Occupation
- Electrician NEC 2020
In Cali the last 10' of the service risor needs to be a continuous piece of Rigid, anything before that could be Emt.
The mast would serve as a point of support for the service conductors which is above the point of attachment of the utility's service drop. The utility's service standard often requires that the point of support for service entry conductors must be above the point of attachment of the utility's supply conductors (service drop) in overhead services. If the point of attachment for the service drop, which is needed to have the clearance required between the service drop and the surface over which it passes, does not leave a higher place to locate the service head on the building that is above the Service drop point of attachment then a mast would be one way of getting the service conductors support point above that of the service drops point of attachment. This is a lot harder to describe than it would be to have a picture of it but I did my best.
Tom Horne
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