Electric wiring is not the most exciting component of a DIY lighting project or an electronics project, but it is one of the most important.
You might go out to get components for your lighting setup, but discover that the cord is too large to squeeze through small slots, too rigid to be bent to fit, or not designed to withstand the environment that you intend to install it in.
Such disappointing failures derail your progress and waste money and time. Fortunately, it is not that difficult to choose the right cord. You need to know the minor yet significant variations between the choices, which will save you hours of trial and error and ensure that your project is installed safely.
This article dissects the differences between the two most popular types of lamp cords, namely SPT-1 vs SPT-2, and helps you decide which one is the best to use for your needs.
1. Insulation Thickness: The Difference between SPT-1 and SPT-2
The most noticeable difference between SPT-1 and SPT-2 comes down to the thickness of insulation. Particularly, the insulation layer of SPT-1 is thinner, and that of SPT-2 is thicker in the areas of the conductors.
Although the difference may not appear significant, it has an effect on the physical behavior of the cord. The finer insulation of SPT-1 increases its flexibility and reduces the difficulty in passing a wire through narrow passages or lamp bases.
In comparison, the heavy jacket of SPT-2 offers additional protection against abrasion, kink, and possible environmental stress. As a result, SPT-1 is likely to be lighter and more flexible in your hands, while SPT-2 is a bit stronger. In projects where flexibility is more important than durability, SPT-1 is usually the one to be chosen.
2. Durability and Protection: Where Extra Insulation is Important
In everyday wiring, it is not only that you are picking the thickness of insulation to achieve flexibility, but it is also for protection. SPT-2 is also more resistant to wear-and-tear and possible nicks or cuts, due to the thicker layer of PVC.
So, when you need to route the cord around the edges, behind the furniture, or in the place where it may be in contact with the rough surfaces, the additional SPT-2 insulation layer can assist in protecting the project. Conversely, SPT-1 has a thinner layer, which causes it to be a little more susceptible to such environments, but otherwise it can easily be used in standard indoor applications.
In this case, therefore, the decision is reduced to the environment: the normal indoor usage maintains the cost low and the ease of use high with SPT-1, but moderate-stress applications enjoy the protective advantage of SPT-2.
3. Elasticity and Simplicity of Installation
Flexibility is a feasible issue for several DIY creators and even professionals. In bending wires into lamp stems, around switch housings, or through tight passages, a cord that bends and does not resist will be much more easily installed. That’s where SPT-1 shines.
It also bends more easily as it has relatively thinner insulation, and it is less likely to crack or kink during the installation process. Even though SPT-2 is not a stiff product at all, its sturdier jacket makes it a little less flexible.
In case you have tight turns or complicated paths, that rigidity may slow you down or demand a little more effort to get the cord in place. If you prioritize a low-friction assembly, you will find that the flexibility of SPT-1 prevails.
4. Environmental Exposure and Usage
Secondly, where will the cord be placed once it is installed? Common indoor applications – such as table lamps, chandeliers, and ornamental lighting – impose very little load on wiring and virtually never need high environmental resistance. In such applications, both types of cord work, but SPT-1 is perhaps a bit easier to work with due to its soft touch.
Nevertheless, when your project exposes your wiring to heat, or your project environment can be susceptible to moisture, the heavier insulation of SPT-2 gives you an added sense of security. Although neither alternative is intended to be used outdoors or in wet conditions, the improved PVC jacket of SPT-2 is more resistant to moderately challenging conditions than that of SPT-1.
Simply put, SPT-1 is typically best used in clean, indoor, and low-stress environments. In contrast, SPT -2 is best utilized in applications where durability and strong insulation are important to long-term performance.
5. Electrical Performance and Safety Standards
A common misconception is that the insulation thickness between SPT-1 and SPT-2 significantly affects power handling. Yet this isn’t the case; both cord types most commonly use 18 AWG (American Wire Gauge) conductors and have the same voltage and current ratings when comparing identical gauges. The insulation layer does not change the amperage capacity of the wire itself.
What it buys you with thicker insulation is better physical protection and broader resistance to mechanical damage. Both types are UL-listed (meeting essential safety standards), making them reliable for residential and commercial wiring when used appropriately.
Thus, neither SPT-1 nor SPT-2 is inherently better electrically, but the insulation quality and construction differences influence real-world robustness.
Final Thoughts
Choosing the right lamp cord doesn’t need to be daunting. Whether you’re rewiring a lamp, building custom lighting, or laying out decorative fixtures, the decision between SPT-1 and SPT-2 ultimately comes down to your project’s specific demands.
If you need a supple, easy-to-route cable for indoor, low-stress applications, SPT-1 offers excellent flexibility and ease-of-use. Alternatively, if your project involves tighter bends, potential abrasion points, or environments that benefit from heavier insulation, SPT-2 gives you that added protective edge without sacrificing safety or performance.
By understanding the practical differences, from insulation thickness and flexibility to durability and safety ratings, you can confidently select the lamp cord that aligns with your goals.
