Whilst specifying a wall mount PSU design, the next decision lies in case type. NetBit offers two different types of cases: horizontal and vertical. However, the terminology can cause some confusion due to the fact this refers to the AC pins, not the plastic case. In this short article we are going to examine the two different types of wall mount cases and help answer some commonly asked questions about wall mount designs.
Wall mount power supply units (PSUs) can have two different AC pin orientations: horizontal and vertical – see the figure below. The orientation of the AC pins in a wall mount design will determine the PSU case orientation when it is plugged into the AC socket. This design feature is therefore an important consideration when specifying a new wall mount PSU.
Typically, a horizontal AC pin wall mount design will have a case that sits below or above the socket. A vertical AC pin wall mount design will have a case that sits to the side as shown in the figure below.
Horizontal AC pin design on left, Vertical AC pin design on right
For PSUs with non-polarized AC pins (e.g. The US NEMA1-15 ungrounded plug) the device can be inserted either way. For PSUs with polarized AC pins (e.g. the UK’s BS1363 plug design) the device can only be inserted in one direction and therefore the case will sit in one orientation.
One important consideration when deciding on the wall mount type is the overall size of the wall mount case in proportion to the power output. PSUs with a power output of 24W or less have compact cases. For higher power outputs such as 36W or 42W the case sizes are larger and dissipate more heat. Typically, a vertical design gives better heat dissipation than an equivalent horizontal design because of the orientation of the PCB and a larger surface area.
Another critical factor to consider for high power designs is the total weight of the PSU. Some AC sockets do not have a high retention force which may cause a heavier or larger wall mount PSU to sag or slump down over time and which could lead to an intermittent connection. If there is a risk of this depending on the region of deployment, then we can recommend using an appropriate wall mount case design that helps prevent the PSU from moving once it is plugged in.
Here are three of the most common questions we get asked about wall mount power supplies:
Question: “What’s your most common wall mount design?”
Answer: Approximately 60% of the PSUs we ship today are horizontal designs and 40% are vertical wall mount designs. However, many of our platforms are available in either orientation and we can match it to your needs. If you’re unsure about the best option for you, please get in touch and we’ll be happy to advise.
Question: “Does a wallmount horizontal or vertical case obstruct an adjoining plug?”
Answer: With a standard AC socket both types of wall mount designs can be used and positioned such that they won’t interfere with the adjoining socket(s). However, there may be some exceptions to this for larger power wall mount PSUs that require larger cases. For higher power use cases we can help advise as appropriate.
Question: Can you have a wall mount PSU with a power output of more than 36W?
Answer: Yes! Due to recent advances in PSU design such as higher power density and greater efficiency, it is now possible to package much higher power designs into wall mount cases. Our current standard platform range now includes a 42W wall mount design available in both single and full AC input range. We also have customized wall mount solutions which can deliver up to 55W of power. These new wall mount designs can offer an attractive alternative to desktop power bricks which can bring about significant cost savings, simpler installations and help eliminate separate AC cables.
Do you have any questions about PSUs that you would like to see us tackle? If so, write your questions into firstname.lastname@example.org. We are always looking to demystify and break down any aspect of CPE PSU design.