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What is Electrical Fitting & How it Works

May. 13, 2021

What is Electrical Fitting


Hi,there!We are coming back.

We got most inquiry about electrical fittings in last few weeks and we learned most of customer has no ideas about electrical fittings details.So we updated this post for you and you will be more clear after reading it.

 

 

Ⅰ What is Electrical Fitting


As you know,the conduit fittings as attachment or accessories for electrical conduit,so we called electrical fitting,conduit fitting or conduit accessories in general.They are used for connect the conduit for easier run the wires in whole house and connect to your electronic appliance.Different conduit has different fitting for connect,you must be pay more attention the size and standard before purchased.

 

Ⅱ What are Electrical Fittings Made of?


There are 2 kinds of materials for fitting on the market,metallic or non – metallic.

The electrical metallic conduit and fittings made of coated steel,stainless steel or aluminum.The coated steel is most common.

And we list most popular metallic tube fitting names on the market as below,

 

(1)   Rigid Metal Conduit (RMC)

A kind of thick-wall threaded heavy duty tube with threaded fittings,it is usually used the outdoor project to protect for electrical cable etc.

(2)   Galvanized Right Conduit (GRC)

Thickness is good,it most applied for commercial decoration or industry construction

(3)   Electrical Metallic Tubing (EMT)

Less thickness than GRC.it is best alternative of GRC because EMT is cheap and lightweight than GRC.Sometimes we called thin-wall tubing.

(4)   Intermediate Metal Conduit (IMC)

Made of steel and heavier than EMT but lighter than RMC.If you hard make a choice,you can pick this one for they are middle option.The middle option is not bad.

(5)   Flexible Metallic Conduit (FMC)

Made of aluminum or steel with a self-interlocked ribbed strip for run the wire.

(6)   Liquid-tight Flexible Metal Conduit (LFMC)

A kind of metallic flexible conduit with waterproof coating inside

(7)   Flexible Metallic Tubing (FMT)

Similar to LFMC but different described as NEC,we think FMT included LFMC conduit.

 

That's the most popular metallic tube on the market.Let’s see the non-metallic one.


(1)   PVC Conduit

The lightest weight and cost-effective materials with the waterproof,fireproof feature.However,the electrical insulation is safer than the metal one for plastic is a natural insulator.

(2)   Reinforced Thermosetting Resin Conduit (RTRC)

The most advantage for this kindly of conduit should be to save your labor cost and meet most of the special requirement.Such as LSZH conduit (Low Smoke Zero Halogen) with V0 fire rating.It is used for indoor and outdoor applications.

(3)   Rigid Non - metallic Conduit (RNC)

Non-metallic tubing with smooth wall tubing.The branch included PVC solar rigid conduit,that’s means the conduit has UV protection feature also.

(4)   Electrical Non -metallic Tubing (ENT)

Thin wall PVC or plastic conduit and used for electrical wire protection.Which has waterproof and flame-retardant features usually.And the corrugated or flexible pipe included ENT too.


The fittings materials just follow the conduit in general,that’s why we talked about conduit materials for this post.

 

Ⅲ The Benefits of Electrical Fittings


Maybe you never thought about this issue seriously, but what happens if we don't have fittings?

 

(1)   Easy to Connecting Conduit & Running Wire

If you don't have a bend or reducer on hand,you will be crazy.

We can't arrange the pipes and wires in a straight line for the whole house which is determined by the geometry.In most cases,it is necessary to turn at the corner and to arrange the wire under or on the wall such as ceiling lamp installed.

However,you need to repair part of the tube sometimes for it is damaged,but you can not replace all of them instead of repair part of a pipe.So the fittings can help you to do this.

(2)   Protect Wires

Good quality conduit can be kept safe of your wire,but it need to match with nice quality fittings too.For example, If you encounter a 90° corner, there is no bend or related fitting on hand.When we run the wire directly and through the pipe, this may cause additional bending and pressure on the wire insulation layer,resulting in whitening of the insulation layer and faster aging.Once the insulating layer fails, there may be a risk of electric shock.

Moreover,a well-sealed conduit will reduce the probability of water and dust entering,which not only keeps the pipe clean, but also protects the safety of the wires.

(3)   Easy to Pull the Wires

If you need to modify the direction or position of the previous wiring for some reason,and we supposed you do not have any special tools.It is the wrong way to pull the wire directly from the right-angle wire tube because this will damage the insulation layer of the wire during the process of pulling the wire,which may cause danger in some cases.Moreover, pulling the wire in this way is easy to get stuck and increasing in construction time.

But if you add fitting when you layout the wires in the early stage,it will be different.The inner wall of the high-quality fitting is smooth and will not damage the wire insulation. More importantly,fittings can make the wires have a certain angle inside, which makes it easier to pull out the wires.

 

We know that people may not pay much attention to the quality of fittings in most cases, especially when it comes to replacement and maintenance at home.

Considering the amount is very small,so you just go to the nearest mall or store to buy a replacement.Therefore,we recommend buy branded products and pay attention to the specifications.So that you will not worry about used for save your time and money.If you want to learn more about the manufacturing process and process of electrical conduit,we mentioned in the previous post, you can read the post named How to Make an Electrical Conduit’ to learn about the manufacturing process of electrical conduit and how to quickly identify the quality of PVC conduit.As for fittings, because most of them are injection molding processes, the identification method is similar.

For readers who don't have time to read carefully,we list some points for effects to product quality.

Whether to use brand new plastic materials for production?

Is the process correct?

Is there a quality inspection following international common standards?

And is the initial mold design reasonable?

These will affect the quality of the product.And we list 6 WAYS to test product quality also in this post.

 

Ⅳ What is the Name of PVC Conduit Accessory & Types of Conduit Fittings?


Per we talked as chapter 1,there are metallic or nonmetallic conduit & fittings on the market.As a professional PVC conduit manufacturer,we only talk about PVC conduit fittings here.And we list the fittings in this post based on Australian standards for we just launched a new project here.

Oh,I almost forgot it.We have been updated the LSZH conduit & fittings catalog for PDF version with pictures,you can download it from our download center.

  

Conduit Fittings Name & How it works

(1)   Bend (Heavy & Medium Duty)

(2)   Solid Elbow (Heavy & Medium Duty)

(3)   Couplers

(4)   Male Adaptors &:Locknuts

(5)   Clips

(6)   Saddle

(7)   Inspection Tee

Ok,let's get start.

 

(1)   Bend

What is Electrical Fitting

It is used to change the direction of the conduit in the home or industry decoration.

We have seen tons of videos on Youtube and shared how to bend the conduit by the heater,this is not best practice because when the pipe is heated and bent,the molecular structure in the middle will change,and even problems such as whitening will occur.Even if there is no whitening,but the bending part will be greatly reduced in strength due to changes in the structure after heating,and it may be damaged after several years of installation and use.

So Bend’s invention is to solve this problem.It can save your time in bending. Moreover,improper operation of the bend can easily lead to the deformation of the pipe.

As for the size,we produce bends with diameters from 16mm to 63mm.For different standards and sizes, we support customized production.

 

(2)   Solid Elbow

What is Electrical Fitting

Many people don't know the difference between Bend and Elbow so that they often confuse the two fittings.The most essential difference between the two is the radius of curvature.Elbow is usually a fixed curvature of 45° or 90°,and the matching diameter is generally 23.5mm-28.5mm. Bend can usually be made larger, even up to 180°, that is, the curvature can be 2 times the diameter or more. Elbow can usually only be 1-1.5 times the diameter.

It is still used to change the direction of the conduit.Now you can choose different products that you want.

 

(3)   Couplers

What is Electrical Fitting

Named couplers or coupling,it is used to securely connect PVC plastic pipes, especially rigid pipes.However,most of the electrical engineering used coupling to fix the damaged parts of the electrical conduit,and it works well.

If you are using a rigid conduit,you need to pay attention to the size when buying a coupling,because it also has different sizes and standards on the market.For example, the size of the couplers we sell ranges from 16 to 63mm.

In addition, if you are repairing water pipes,you also need to use special glue on the coupling to ensure that there is a good connection and no water leakage.


(4)   Male Adaptors &:Locknuts

What is Electrical Fitting

Similar as Connectors of US standard (UL Listed),it used to attached the attach conduit to an electrical box or adaptable box,and the set included adaptors and locknut for quickly & easier connect with adaptable box or j box,then save your labor cost when installed the conduit.

The size still same as the electrical conduit from 16 to 53mm also,the US size will be in here.You need to pay more attention before purchase.

 

(5)   Clips

What is Electrical Fitting

Clips (or Clamp) are necessary if you got a long run for your conduit because the conduit will be sag naturally if got a long run without any support.However,the conduit will easy to break if hang it a long time.

Once you install the clamp,the rest is so easy,you just install the fixing screws of the base,and the conduit can be firmly fixed on the wall or ground,and there is no need to worry about the conduit being damaged due to incorrect position.BTW, In addition, some customers from AU even customize this accessory because they need a self-locking device, so that a clip rows and it is more convenient to arrange the pipes.

 

(6) Saddle

 

What is Electrical Fitting

Another kind of clamp,and still designed for support the long conduit purpose.They prevent sagging and break by own weight too.

The difference between the two are materials and fixed.Obviously,the saddle is made of metal and clip made of plastic.However,the saddles have reserved 2 big holes for screw access,so that they can be fixed on the wall more easily.And the clips have 1 hole for screw access only.

 

(7)Inspection Tee

What is Electrical Fitting

Similar to conduit bodies in US standard and used for connecting conduit for run the wires.There are different 3 ways with 90° to change the direction of the conduit.

Moreover,the lid on the top of it can be easily opened to check and maintain the condition of the circuit at any time.Allows you to quickly check wire problems in sections.

 

That's all of the fittings for AU standard,please contact us if you have any questions here.

 

Ⅴ Why PVC Fittings?What are the benefits of PVC Fittings in Your Project?

 

In general, the main benefits of PVC fittings are insulation,heat insulation,lightweight, easier design and processing,long-lasting(with a certain range of deformation tolerance),low production cost, and recyclability.

 

(1)   Electronic Insulation

You must know PVC or plastic is a natural isolator,this is a huge advantage compared to the metal electrical pipe.

We suppose the wire is broken in the conduit,and the metal is a conductor (of course, the current metal tube has insulate coated or plastic insulator), but if the insulation layer fails, then it will still conduct electricity,which will cause serious consequences and even threaten our safety.

 

(2)   Heat Insulation

Similarly,the thermal conductivity of metals is also very good,but if they are used in outdoor projects,such as solar power stations,the excessively high temperature may not only cause the risk of burns,but the most important thing is that it may cause premature aging and damage to the internal wires which produced spontaneous combustion and other consequences.

On the contrary,PVC plastic wire tubes have poor thermal conductivity,so they can perfectly match with harsh outdoor working conditions to ensure safety.

 

(3)   Light Weight

Because the density of general plastics is smaller than metal,so the weight of plastic electrical pipes is much lighter than comparing with metal conduits of same size.This not only saves a lot of labor costs during construction,but also makes maintenance easier.

In addition, during the construction period,there is no need for extra mechanical equipment or tools assistance comparing with as metal electrical conduit,so it is more environmentally friendly.

 

(4)   Easier Design and Processing & Long - Lasting

The production process of plastic products is now very mature.For example,our common extrusion and injection molding processes have been widely used all over the world for many years,and the cost is relatively low.In addition to our electrical pipes,let’s compared them with children's toys.The shape is ever-changing but still stable,which is enough to explain the problem.Moreover,the processing technology of plastics gives designers more imagination.Such as change colors? Increase the pattern? The needs you can now be solved only take few days. The cost and complexity of metal processing are definitely higher than that of plastic products.

As for the durability of plastic products,i believe everyone has a deep understanding of it in daily use.Because the plastic itself is a non-degradable raw material and is relatively less affected by the surrounding environment,there is no problem with durability too.

 

(5)   Low Production Cost & Recyclable

As we mentioned before,considering the production process is simpler,so the manufacturing cost is lower than the metal conduit,which is easy to understand.That’s why our customers can buy plastic products at lower prices.This leads to the biggest influence factor on product prices is raw materials price now.

As for recyclables,I think everyone is no stranger to it.Our children's toys are old and no longer used,we can donate or recycle them.Up to now, most plastic products can be recycled.Of course, these recycled raw materials can only be limited used such fields or products with lower requirements.But this not only greatly saves raw materials,but also avoids pollution in the production process,then protecting our environment.

 

Safety & Standard Issue


Based on US NEC files,the Rigid Nonmetallic Conduit (RNC) Uses not permitted,

 

Hazardous locations — PVC conduit isn’t permitted to be used in:

• Hazardous locations except as permitted by Sec. 501.10(A)(1)(a), Exception; Sec. 503.10(A); Sec. 504.20; Sec. 514.8, Exception No. 2; and Sec. 515.8.

• Class I, Division 2 locations, except as permitted in Sec. 501.10(B)(7) [Sec. 352.12(A)]

Support of luminaires — PVC conduit isn’t permitted to be used for the support of luminaires or other equipment not described in Sec. 352.10(H) [Sec. 352.12(B)]. PVC conduit can support conduit bodies in accordance with Sec. 314.23(E), Exception.

Physical damage — PVC conduit isn’t permitted to be installed if subject to physical damage, unless identified for the application (Figure).

Schedule 40 PVC conduit is not identified for use where subject to physical damage. PVC Schedule 80 conduit is identified for use in areas subject to physical damage [Sec. 352.10(F) Informational Note].

Ambient temperature — PVC conduit isn’t permitted to be installed if the ambient temperature exceeds 50°C (122°F) [Sec. 352.12(D)].

 

So we recommend you just follow NEC's requirement and do NOT against the rules,especially do not use the physically damaged conduit.

 

At last,we would like to show some UL standard test details here because most readers or customers ask us these questions.

Again,we hope readers and buyers purchased qualified products and stay away from danger.We know most of the inferior products can NOT pass UL651 test (espically some non brand sch 40 and sch 80 conduit & fitting on the market).

 What is Electrical Fitting


UL 651 8th Edition Test for PVC Conduit (Released Oct 25,2011)


 What is Electrical Fitting


 

UL651 for Conduit Fitting Test

 

That's all of this post,we hope you have learned about electrical conduit fittings,you can contact us in contact form or email if you have any questions.

Take Care!


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