Metric Sizes for EMT

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fifty60

fifty60

Senior Member
Location
USA
I have 1 1/4" EMT that I need to convert to the equivalent metric size. I am finding that 35mm is the equivalent metric size, but I did not know if that is an exact measurement or an approximation. If i ordered a "trade size metric" 35 EMT, would i be getting the same thing as ordering a 1 1/4" EMT?
 
Besoeker

Besoeker

Senior Member
Location
UK
fifty60 said:
I have 1 1/4" EMT that I need to convert to the equivalent metric size. I am finding that 35mm is the equivalent metric size, but I did not know if that is an exact measurement or an approximation. If i ordered a "trade size metric" 35 EMT, would i be getting the same thing as ordering a 1 1/4" EMT?
Click to expand...
It is a bit bigger.
 
gadfly56

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
The actual size for 35mm is 1.5118/1.3819 in OD/ID, and 1-1/4 in is 1.510/1.380 in OD/ID, but that's based on US charts. At least as best as I can determine. It's tough finding a catalog cut from a European manufacturer of metallic tubing for electrical work. Either they don't generally use it, or I just don't know what it's commonly called. I found one catalog from Hegler, and the nearest actual trade size they show is 32 mm. It has an OD of 32 (-0+0.4)mm and an ID of >=30.6 mm, so nominally 1.2598 in and 1.2047 in.
 
Besoeker

Besoeker

Senior Member
Location
UK
gadfly56 said:
The actual size for 35mm is 1.5118/1.3819 in OD/ID, and 1-1/4 in is 1.510/1.380 in OD/ID, but that's based on US charts. At least as best as I can determine. It's tough finding a catalog cut from a European manufacturer of metallic tubing for electrical work. Either they don't generally use it, or I just don't know what it's commonly called. I found one catalog from Hegler, and the nearest actual trade size they show is 32 mm. It has an OD of 32 (-0+0.4)mm and an ID of >=30.6 mm, so nominally 1.2598 in and 1.2047 in.
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I don't know about the rest of the EU zone but, in my experience, EMT is rarely used here in UK.
Actually, I had to ask forum members here what EMT meant.
Conduit we'd call it.
 
gadfly56

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
Besoeker said:
I don't know about the rest of the EU zone but, in my experience, EMT is rarely used here in UK.
Actually, I had to ask forum members here what EMT meant.
Conduit we'd call it.
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Is it that EMT specifically is rarely used, or that metallic conduit of any type is rarely used?
 
B

Bladnaster

Member
Location
CT.
Someone correct me if I'm wrong, but in the US, 1 1/4 is designated as 35mm for sizing purposes.

If you ask for 35 mm in the states, after some odd looks, they will give you 1 1/4 conduit. It is the same.

The exact measurement of 1 1/4 converted into mm would be 31.75mm.

Now why the US didn't just say 32mm is beyond me. Regardless, they call it 35mm which is not an exact measurement, but more of a designation.

If you actually need 31.75 mm....well, good luck because I have no idea. Would someone have to order from overseas where the metric is the standard in this case?
 
gadfly56

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
Bladnaster said:
Someone correct me if I'm wrong, but in the US, 1 1/4 is designated as 35mm for sizing purposes.

If you ask for 35 mm in the states, after some odd looks, they will give you 1 1/4 conduit. It is the same.

The exact measurement of 1 1/4 converted into mm would be 31.75mm.

Now why the US didn't just say 32mm is beyond me. Regardless, they call it 35mm which is not an exact measurement, but more of a designation.

If you actually need 31.75 mm....well, good luck because I have no idea. Would someone have to order from overseas where the metric is the standard in this case?
Click to expand...

Except that 1-1/4 trade size isn't 1.250" in any dimension, anymore than 1-1/4 schedule 40 pipe is. See my post at #4. It looks like the actual European trade size is 32 mm, which is in fact very nearly 1.250" in OD.
 
B

Bladnaster

Member
Location
CT.
gadfly56 said:
Except that 1-1/4 trade size isn't 1.250" in any dimension, anymore than 1-1/4 schedule 40 pipe is. See my post at #4. It looks like the actual European trade size is 32 mm, which is in fact very nearly 1.250" in OD.
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If he happens to be working with European equipment, then I dont know.

In the US, 1-1/4 is designated as 35mm to the best of my knowledge.

So in the US, yes, if he ordered trade sized metric emt, he would be getting 1 1/4 inch pipe. Will it affect whatever application he is applying it to? I dont know.
 
GeorgeB

GeorgeB

ElectroHydraulics engineer (retired)
Location
Greenville SC
Occupation
Retired
Besoeker said:
Of any type.
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When a motor has a wiring box, what size fittings are used for your cables? Are no-some-all of the wiring boxes threaded? I don't know whether all of the EU is identical or not ... you Brits (if that is a derogatory term, I apologize in advance) use inches too, I remember.
 
Besoeker

Besoeker

Senior Member
Location
UK
GeorgeB said:
When a motor has a wiring box, what size fittings are used for your cables? Are no-some-all of the wiring boxes threaded? I don't know whether all of the EU is identical or not ... you Brits (if that is a derogatory term, I apologize in advance) use inches too, I remember.
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I don't consider it in any way a derogatory term. I am British.
Inches....we used to.
Engineering is now all SI.
 
LEO2854

LEO2854

Esteemed Member
Location
Ma
fifty60 said:
I have 1 1/4" EMT that I need to convert to the equivalent metric size. I am finding that 35mm is the equivalent metric size, but I did not know if that is an exact measurement or an approximation. If i ordered a "trade size metric" 35 EMT, would i be getting the same thing as ordering a 1 1/4" EMT?
Click to expand...
If you look in Annex C of the NEC the sizes are listed.


imagejpg1_zps7aad700f.jpg


Looks like I can start running 155 (6") EMT....:lol:
 
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