This video clip covers everything you need to know around working v EMT (electrical metallic tubing) together an electrician. Ns cover the topics debated in the national electrical code write-up 358 on supplies permitted, securing and also supporting, and also much more. This video is an ext of a code-overview of EMT, so let’s start at the start of short article 358 of the NEC through the supplies permitted and not-permitted.

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WHAT IS EMT?

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EMT stands for electric metallic tubing, and is a thin-walled raceway the electricians usage to pass conductors through. The is often called a conduit in layman’s terms, however it is an ext specifically a kind of tubing. EMT is used indoors and also outdoors, and also there space several types like Aluminum, Galvanized, and Stainless that deserve to be offered in various situations and also at different price-points.

358.10 – provides PERMITTED

EMT is enabled to be supplied in dry, damp, and wet locations and in concrete or direct contact with the earth as long as you monitor 358.10(B)

There room different varieties of EMT the have different properties as well, for this reason make sure that you’re using the correct form in the correct environment prior to making presumptions that everything is ok for basic use. For instance Aluminum EMT is not approved to be direct buried unless there’s a supplimentary coating or protection about it – conversely, stainless steel and galvanized stole EMT space allowed.

358.12 – uses NOT-PERMITTED

You cannot install EMT where it is subject to physical damage, or whereby it is supplied as a support for a luminaire or other equipment. For both of these RMC (rigid steel conduit) would certainly be acceptable. So if you’re working in parking garages near vehicle traffic, or in corrosive environments where the EMT may obtain damaged, you should use a better method favor Rigid to protect your conductors.

358.14 – DISSIMILAR METALS

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Galvanic action is a serious problem to look right into when dealing with dissimilar steels touching each other. A many of human being don’t think around this when installing conduit, but the nature of two various metals is that among them is an ext active and also the other is much more passive. The more passive metal will begin to weaken/corrode the an ext active metal and also over time may damage the energetic metal. This is particularly dangerous as soon as using EMT together an equipment grounding conductor. Over a long enough time, that one complete conduit system might turn into several disjointed segments due to corrosion, leaving you through no tools ground.

358.20 – SIZE

There are minimum and maximum trade sizes that are enabled to be offered as EMT. They should be no smaller sized than 1/2″ and no larger than 4.” you can’t simply take a item of 6″ pipe, slap some conductors in it, and also call the EMT.

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358.24 and also .26 – BENDS

348.24 particularly talks around ensuring that once bending conduit, your bends are not damaging the inner diameter of the tubing, and not to reduce the diameter of the tubing. This renders damaging the conductors inside more likely, and more daunting to traction in or out.

358.26 Talks about how many bends you have the right to have in one complete run the EMT – from crate to box, or pull point to traction point. The max for many conduits/tubing is 360 degrees of bends. Therefore that way no more than 4 90-degree bends from one box to another. The more you perform this you’ll view why this is – it’s daunting as hell to get conductors traction through, and much more often than no you damage the insulation that the conductors as soon as pulling both in and out – if much more than 360 degrees of bends exist in the run.

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358.28 – REAMING

This section calls for you to ream, or clean, the within of any type of newly reduced conduit prior to installing it. As soon as cutting EMT friend will often times have an extremely sharp inside edge that conductors can be damaged by pulling across these edges. That on you to clean the reduced end of the conduit in whatever means you watch fit, and the NEC no say you have to ream with any certain tool. Many people carry with them a reaming-screw-driver to do this task easier, but I’ve watched others use channel-locks, pliers, needle-nose, various other pipe, and a whole host of other methods. The end result should it is in a clean inner and outer edge at the newly reduced edge.

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358.30 SECURING & SUPPORTING

With many other strictly conduits and also tubing the 10-foot ascendancy still uses to EMT. This means that you must securely assistance EMT no more than every 10-feet. This means you deserve to strap the every 3 feet if girlfriend want, simply not much more than 10 feet between straps/supports.

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This section also requires you come strap within 3-feet of any box, panel, or termination suggest for the conduit run. That’s not an overwhelming to remember. From your panel or box, operation your conduit up, strap it in ~ 3 feet that the panel, climate every 10 feet ~ that. Currently I will certainly say THIS IS THE MINIMUM standard – meaning I personally choose doubling increase on straps therefore a many times ok strap in ~ 3 feet that the panel, then every 5 feet after. This is within the standard, and EXCEEDS the standard. Inspectors appreciate once you exceed standards, yet they hate as soon as you fall short of them.

358.42 – COUPLINGS & CONNECTORS

Couplings and also connectors need to be consisted of tight, and also when set up in concrete or wet areas must be authorized for the use. This is exceptionally important since EMT is considered an tools grounding conductor in 358.60. If any part of the EMT mechanism is not tight, you shed the reliable ground-fault path and could potentially shed your ground if use this method. This is an extremely rare nowadays but you execute see it in older systems that you come across.

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**Disclaimer – this videos space for training purposes alone, all work-related done on electric systems need to be done by a licensed and also insured electric contractor. If you room not an electrician, perform not attempt any of the work-related you space seeing in these videos.**